Tuesday night at the Observatory, while local heroes Thricewere giving their final (for now) show after 14 years together, I took an informal survey among friends and acquaintances, drunks and doormen. Just how long, I wondered, do they think it will be before the band calls off its indefinite hiatus and announces a reunion tour?

Three years – that seemed to be the general consensus. Five years at the very most, and two isn’t out of the question. Couldn’t tell you if frontman Dustin Kensrue agrees with any of these assessments — I doubt he has an inkling himself. But as the quartet was about to play its final song, “Anthology,” during a one-shot encore that followed 32 other tracks in three sets across nearly three hours, he alluded to an inevitable return.

“You guys are amazing, we love you,” he told the teeming throngs that packed the Santa Ana venue, along with another 30 or 40 fans who milled about outside hoping to at least listen. “There’s never been a place that rivaled home. We’ll see you in the future at some undisclosed time.”

Color me fatalistic, but I predict that time may never come – or at least nowhere near as soon as everyone imagines. I suspect that’s why bassist Ed Breckenridge looked so inconsolably sad as he walked away from the stage. Something tells me they know this is The End.

Why such a bleak outlook? Because for as much as Thrice outwardly plays nice, publicly portraying this temporary break as an amicable decision, the reality seems a lot closer to a genuine rift among members.

Yes, Kensrue has a wife and kids (their third is on the way) with whom he’d like to spend more time, rather than live on the road. Guitarist Teppei Teranishi has a similar situation at home.

But that isn’t the only reason for the split. An arguably more dominant influence may have come from Kensrue’s involvement with Mars Hill Church, the controversial evangelical organization, whose Santa Ana headquarters are directly in front of the Observatory. The singer-songwriter serves as worship director at the megachurch’s local chapter. He’s often seen performing Sunday mornings and afternoons in this very venue, albeit in a different capacity.

Much like the guys in Thrice themselves, true gentlemen who rarely discuss private matters, I’d prefer to steer clear of questioning how one chooses to uphold faith in a Higher Power. None of my business, really. I also don’t want to get too far afield of what this farewell means for the band, and how it went down a riot Tuesday night, by instead focusing too much on the alleged machinations of Mars Hill.

Things like, oh, to what degree is founder Mark Driscoll a misogynist? (He pushes a hard line about men being masters of their households, among other less charitable views toward women.) Or whether Mars Hill’s totalitarian approach toward fully paid-up congregants (think Mormonism) seems to have less to do with aspiring to the goodness of Jesus and a lot more to do with behavioral control (think Scientology). My two cents: When something looks like a cult and acts like a cult, it’s probably a cult.

From that context I want to consider chiefly this: Before Thrice had even begun this final run of farewell shows (which included two nights at House of Blues Anaheim and another sell-out at Club Nokia before these last blasts at the Observatory), Kensrue revealed on his Twitter feed that he’s already busy working on material with a new band. “Grace Alone” and more from a five-song EP, presumably aimed at the contemporary Christian music (or CCM) market, is due later this summer via Mars Hill.

That doesn’t sound like the doings of a creatively spent guy who wants to slow down and stay home. More like someone who wants a change of scenery — and who perhaps has faced some pressure from his pastor to shun a certain lifestyle. I’ll bet this much: You’ll see Kensrue, either as a solo artist or with his new group, performing at a Fishfest, like this Saturday’s tobyMac-led event in Irvine, well before you’ll see Thrice resurface.

So it’s a very good thing the band ended things on such a high note. That goes both for this Observatory gig — an epic performance culled from all points in their catalog that will loom large in their legend — and their career in general, which had reached personal-best peaks with the last two albums, 2009’s turning point Beggars and its tension-filled follow-up Major/Minor, from last September.

Yet that’s also what frustrates me, that they’ve ended now, just as their music has grown so much better. I know fans of The Illusion of Safety and The Artist in the Ambulance, the group’s formative breakthrough albums, will disagree with this thinking, but Thrice had just begun to get really interesting in recent years by steering its music into more progressive (and rewarding) Radiohead-esque realms.

Various volumes of The Alchemy Index (2007-08) helped shatter their mold of cathartic aggression and Deftones-heavy grime so that they could rebuild it into something deeper, sonically adventurous, less predictable. This was a band, one of the biggest grass-roots successes to ever emerge from O.C., maturing in the most fascinating of ways, with a limitless horizon ahead of them. And now they’ve been derailed, forced into possibly permanent limbo by one member’s wish (or should that be ambition?) to pursue something else.

Kensrue shouldn’t be faulted for that. His true calling is for him to sort out, and Thrice is too tight a brotherhood not to support him. But the more he slips into the CCM machinery, the more likely I think it is that he won’t come back. Never mind how lucrative that insular scene can be. More crucially, cultivating that audience could repel a good chunk of his existing fan base – not because they loathe Christians who wanna rock (plenty are just as devout) but because they love Thrice so much and wouldn’t prefer overtly religious songs.

Pop history is littered with talented people who stopped selling once they found God. Walking away from what made his reputation could breed ill will: the same crowd that would wait a decade for Kensrue’s return might not hang around if he steeps himself too thickly in faith-based rock.

I can’t have been the only one thinking this stuff between sets Tuesday. You could tell the mood wasn’t entirely celebratory in virtually every corner of the Observatory. By happenstance I was backstage moments before Thrice went on – they didn’t exactly seem thrilled, either, their camaraderie noticeably muted. Despite the intensity of the crowd’s cheers, there was a great deal of solemnity coursing through the room. The mosh pit flared up as anticipated, but further back you could sense more sadness than elation.

A powerful experience, yes, but hardly a hopeful one. Yet it was a performance no one there will soon forget, a marathon spanning Thrice’s history, from neglected tracks off their often disowned 2001 debut Identity Crisis (people went absolutely ape when “Phoenix Ignition” led to “T & C” late in the night) all the way through to the best bits from Major/Minor, including an endearingly flubbed reading of “Disarmed” during Kensrue’s acoustic portion between the two main sets.

(Frankly, I could have done without that entirely, or at least demanded the whole band participate. Seemed self-indulgent and narcissistic to include a solo spotlight on such an auspiciously glum occasion for Thrice as a whole, which has always been more than the sum of its parts. Tacking on an acoustic mini-set as a secret coda, after the encore, as Kensrue did after Monday’s show – that makes much more sense.)

The energy ebbed and flowed amid the first set, depending on the song, but by the second half there was only mounting insanity. Moshers collapsed one upon the other, like waves on a stormy sea, as Teranishi added a Hammond organ facsimile to a roaring rendition of “Identity Crisis,” then joined the others in a stomping rip through the Beatles’ “Helter Skelter.”

By the time inflatable beach balls filled the pit for “Under a Killing Moon” and “Deadbolt” – after which Kensrue went stumbling into the crowd at the end of “To Awake and Avenge the Dead” – the aggression down front had turned violent, the enthusiasm at the rear of the venue causing people to spill over tier partitions.

Through it all, Thrice played stronger and tighter than I’ve ever seen. There wasn’t much evident joy on stage, apart from a smile here or there. But the fury they conjured, more explosive with each song, was astonishing.

The Breckenridge brothers (including fierce drummer Riley) locked in as only siblings can; Kensrue and Teranishi unleashed one last dose of screaming mania. All of them deftly traversed tricky time changes, martial rhythms, sludge that turns to space-rock as fast as dirt turns to mud, and atmospherics pitched somewhere between King Crimson cool and Tool madness.

They played as they should have — like it was their last show forever. Hope I’m wrong, because there’s so much more Thrice is capable of achieving. But I can’t help feeling like this will remain their swan song.

Setlist: Thrice at the Observatory, June 19, 2012

First set: Yellow Belly / Image of the Invisible / The Artist in the Ambulance / Kill Me Quickly / Hold Fast Hope / Blood Clots and Black Holes / Silhouette / In Exile / The Weight / Promises / Broken Lungs / Daedalus / Words in the Water / Of Dust and Nations / Red Sky

Dustin Kensrue acoustic set: Come All You Weary / Madman / The Whaler / Stare at the Sun / Disarmed

Second set: Firebreather / The Messenger / The Earth Will Shake / Identity Crisis / Helter Skelter (The Beatles cover) / Beggars / Phoenix Ignition / T & C / Stand and Feel Your Worth / Under a Killing Moon / Deadbolt / To Awake and Avenge the Dead

Encore: Anthology