Why did John Mason risk the incinerator in "The Rock" when he could have used the door?

Question

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 that didn't quite sit well in my head.

In the scene where the FBI (and John Mason) arrive at "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 sees 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?

Answer 1

While in full operation, all the doors would have had to have been opened from a central operation point, just like cell doors. Those doors would have sounded alarms if randomly opened by prisoners. By rolling through the incinerator, he would have been able to avoid detection while passing from the hallway to the incinerator room.

That being said, there are still huge plotholes throughout; the least of which is how he remembered the timing after however long it's been (I don't recall how long he was in jail before they pulled him out for this Op).

Answer 2

Perhaps when the prison was active, the doors were locked from the outside to keep people in.

Once the prison became more of a tourist attraction, the doors were locked from the inside to keep unauthorized visitors out.

Answer 3

The door could've been guarded when Mason was escaping.

And even if it wasn't, there is no way to close that door once he left. If he went through there, some guard could easily spot the opened door and sound the alarm. This would be a huge problem, because it was crucial for Mason to get as far away as possible before it is found out that someone is escaping. An escape from The Rock does not end once a prisoner is just outside of the walls.