To my surprise, on this run, gas chamber get quite overpressurized (15 000 g and rising). it's quite nice, because I have not reach plastic and high pressure vent yet. My guess is that the little bit of polluted oxygen (16g) on top is sensing the geyser that atmosphere is below 5kg (or the tiles?). My question is: do you know where the geyser is sensing to see if overpressured or not?