When Paulo was watching them from the bathroom, I thought that when they left, they went through a metal doorway which they closed behind them.

I assumed it was an entrance to a tunnel. But I guess it could have been the doorway leading to the ladder.

I hadn't thought about that until your question.

__________________
charlie98210
"Whoa!" she said. "Cry 'Havoc!' And let loose the dogs of war!"
And, like Banquo's ghost, they just won't go away.