About 2,500 people were on the stream, listening and commenting over how long it would take before Ruffalo ended the broadcast.

Ruffalo and the crowd could be heard laughing at scenes. Audio from the film was clearly audible.

Around 8:15 p.m., Ruffalo stopped the live feed. It is unclear if someone told him it was still running or if it cut out on its own.

To prevent pirating, Marvel had audience members at the premiere turn off their mobile devices and allowed security staff to lock them in sealed pouches before entering the theater. After the screening was over, security unsealed the pouches for guests on their way out so they could once again use their phones. But those rules don't apply to superheroes, obviously.

See some reactions to the accident below:

mark ruffalo accidentally staying on instagram live while watching thor just made my day pic.twitter.com/CdLGPsDZKH — caroline reid (@lizzieolses) October 11, 2017

@MarkRuffalo i think you accidentally spoiled the movie and Marvel is judging you from afar now. #ThorRagnarokPremiere pic.twitter.com/bmhtOC1lUN — Susana (@reidikulus) October 11, 2017

mark ruffalo what are you doing HAHAHAHAHAHHAAHHAHAHA — ragnarok gen (@hiddlest4rk) October 11, 2017

Mark Ruffalo is gonna get in trouble again — Mikee Kong (@robelissimo) October 11, 2017

Marvel is gonna whoop Mark Ruffalo’s ass — sarah (@finnreyz) October 11, 2017

lol mark ruffalo forgot to turn his ig live off so he spoiled some parts of the movie — (@beaaarrrr) October 11, 2017

I feel bad for him but at the same time I can't stop laughing Mark Ruffalo everone — melissa solis (@melimukeaf) October 11, 2017

Oct. 10, 11 p.m. Updated from details from inside the premiere.