When playing the Break out event, players are likely to pick a wide range of different heroes, who all have different "hooks" to get them into the adventure. This will likely start all the players in different locations and complicate getting them all in the same place.
This situation could be fun itself, but say you want it to be a little less complicated--you want to get right tot he action, or maybe you have a group of first time players so you want to simplify it a bit and start them all out together.
My advice is to start them all out visiting the raft to speak with Sentinal. They will all take a tour of the facility (just like in the comic) and get down into the lower levels--and that is when the breakout begins.
Youll have to change some of the characters hooks to do this. As is, Luke Cage, Daredevil, and Spiderwoman already start in this situation, but Spiderman starts in his aparment, Iron Man off somewhere.
So instead, you change Spidermans hook to be that he is there to take photos of Sentinal for Daily Bugle or something--thats why he is along, and maybe Iron Man is there too to "inspect" the facilities technology. Basicially, you just have to give all the characters some excuse to be on this "tour"
This will simplify everything by starting all players together and starting them deep down inside the raft where they have to fight their way to ask Sentinal for help, and then fight their way out.