This has been a problem for a couple of people so I promise I will implement a fix. At the moment, once you hit 100 heat, that is it, you are finished. A variable gets set that triggers the end the next time you go in the hallway and bringing heat back down does not change that.
However, this is clearly creating unintended expectations of the situation, so I will either make it that you can save yourself, or make it clear that you can not. Not sure which way I'll go atm.