I just watched an old classic, The Rock (1996) with Nicolas Cage and Sean Connery, and, while watching it, I noticed something I hadn't noticed before which didn't quite sit well in my head.
In the scene where the FBI (and John Mason) arrive to "The Rock", the first challenge is to roll through the incinerator. While asked about how John Mason would accomplish to get by the incinerator, he answers
I memorized the timing. I just hope it hasn’t been changed.
Of course, he rolls through the flames, and ends up opening the door for the other agents, so they don't have to go through the incinerator.
So, here's my puzzle: John Mason is brought along because he has escaped from Alcatraz. Now he is breaking into the place, so we must assume that the way the audience see is the opposite of what he did when he got out.
So why the need to memorize the timing and risk his life through the incinerator, when he could much more easily and safely just open the door and go out that way?