Think you know how the Thanos arc is going to end? Think again, because Mark Ruffalo just said that even the Russo brothers may not even know how this will go down.

On The Marvelist podcast, the actor who plays the Incredible Hulk/Bruce Banner said that during re-shoots, the actors are still working off of dummy scripts and are not sure what the ending is going to be:

“We don’t even know what it’s gonna be yet. We’re not just doing reshoots. We’re going to finish the movie, which we really didn’t get to finish totally when we left it last year.

I don’t even know that [the Russo’s] really know exactly. Some of it is happening while we’re there. It’s pretty amazing. And we’ll shoot some stuff and a few days later come back and reshoot it ’cause we wanna take it in another direction. It’s a very living organism; even as we approach it being a locked picture, we’re still working on it.”

Most likely, Captain Marvel will be making an appearance, if not playing an important part, but it seems like nothing else is set in stone. This fluidity of script could be in part due to the turmoil of Guardians of the Galaxy 3 and James Gunn, but there could be other factors behind the screen as well. Either way, Mark Ruffalo seems to be taking it in stride, so that’s a positive.

What ending do you think they’ll go with? Leave your theories in the comments below!

The currently untitled Avengers 4 movie is set to premiere in theaters on May 3, 2019.