Justin Turner entered the players’ bus, the last Met to do so yesterday, and with that, the mini-fleet of two vehicles departed Citi Field, not to be seen again for 11 days.

If things continue at the rate they’ve been going? By the time Mets return to this time zone, they’ll be in last place. They’ll have a disabled list long enough to play a full-court basketball game. And they’ll inspire Kevin Costner, always up for another baseball flick, to make a sequel to his “Hatfields & McCoys” mini-series.

You’ve got to give props to these Mets. They don’t merely slump. Year, after year, they spontaneously combust. They come apart at the core.

To see Terry Collins and Josh Thole speak yesterday, following the Mets’ 5-2 loss to the Nationals — their 11th loss in 12 games since the All-Star break and 12th of 13 overall — was to see a ballclub in danger of imploding. Forget about making a miracle playoff run. At 47-51, these Mets’ first goal is to stop embarrassing themselves.

“Once in a while, when things go bad, you start making excuses, and I don’t deal with excuses,” said a fired-up Collins, who shared these sentiments with his players in a postgame meeting. “I deal with accountability. I deal with standing up and being a man. Standing up and being a professional baseball player. And playing the game right.”

Said the normally placid Thole: “I don’t think anything can be worse than this right now. I can’t wait to get out of here.”

Thole found himself in the middle of an unwelcome scene, after Adam LaRoche’s two-run, seventh-inning homer off Mets lefty Tim Byrdak bumped up the Nationals’ lead to 5-1. The SNY telecast showed Byrdak staring at Thole and expressing his unhappiness with the pitch selection to the lefty-hitting LaRoche. Then Byrdak, immediately lifted from the game, had what appeared to be a tense conversation with Mets pitching coach Dan Warthen.

“I got frustrated with it,” Byrdak said. “I didn’t want to throw that fastball there. I wanted to throw a breaking ball. I didn’t execute the pitch.”

Byrdak appeared contrite, and he said he apologized to Thole, who said, “It’s what happens when you lose 11 out of 12 games, or whatever [the number is].” Warthen didn’t make himself available for comment.

Slumps happen, tantrums happen, rifts happen. Where these Mets have to differ from their recent predecessors is they must fix this expediently. Not let it fester and grow as often seemed to be the case under different general managers and managers.

This isn’t a very good baseball team. It isn’t a horrible one either, though. Its true identity is probably about a 78-84 team, the pace they’re on at this moment. That means not playing any worse than this, though. It means finding solid ground, starting tonight in Arizona when Matt Harvey makes his major-league debut.

BOX SCORE

“Two weeks of the season of the second half is not the season we’re going to have,” David Wright said. “It’s going to be good to get on the road, hopefully start a nice streak on the West Coast. We can’t go back and try to get these last couple of weeks back in one game. We have to slowly gain back the confidence we had in the first half.”

The Mets aren’t about to start buying bullpen help, not in their current state, and as The Post’s Joel Sherman reported, they’ll consider selling semi-valuable pieces like Byrdak and Scott Hairston, but pull the trigger only if they get players who can help for 2013. Most likely, they’ll proceed as is through Tuesday’s non-waivers trade deadline.

They need to change their vibe, however. Get back to being a happier group, even if they won’t fully recapture their first-half magic. Turn yesterday’s incident into an aberration.

Come back home in one piece and preaching peace.

kdavidoff@nypost.com