Eleven hours until the stairwells open, seventeen until the floor collapses, and the whole plan has to fit in the gap.
The clock hangs over the chapter: Time to Level Collapse, 17 Hours; Time to the Opening of the Stairwells, 11 Hours. Every decision is made against it — Carl telling Imani C there is a lot to do and not much time to do it, the party rushing the cart before the next wave of red dots, and the whole soul-crystal plan being something that must be done before the stairwells matter.
Prepotente's account confirms the stakes: killing a Province Boss would have blown multiple Soul Crystals and chained a reaction through the entire system that would let their fellows proceed to the next floor. The stairwell openings are what everyone is trying to survive to reach.
The countdown structuring the endgame: eleven hours to the exits, seventeen to the end of the floor.