I think it is probably right to push, but just calling is really awful. You have to play 4 handed not even in position. Almost any flop is scary, especially with none of their hands pegged at all. I'm not sure how this would work out, but I know with a lot of really big donks, they are afraid to go "all in". Maybe raising to like 500 trying to isolate the donk could almost guarantee his call and let you out on an A/K flop. That said, I think I push.