This morning I’ve added a sprinkler control system (one-shot, unfortunately), and closable fire doors. You can see both above. In nethack tradition, + is a closed door while - is an open door.
Doors give lots of interesting possibilities. I decided to make most passageways have doors, as they make interesting decisions. Should I dive for that door to block off the fire, or to open it to let a flood through? Or do I not have time? I’ve left most open at the start, but closed is sometimes helpful, sometimes not.
In the screenshot, the S next to the player in the bottom right is the sprinkler control panel. Before it’s used, it’s bright yellow. I’ve added sprinklers so there’s more than one objective in each floor. If the exit is blocked, maybe the sprinklers will push back the fire enough to let you in. Or maybe you have a roughly evens chance of making the exit before the fire - but how would those odds change if you made a b-line for the sprinkler system instead?