At the base of the stairs, you realize what has been giving off that heat:
A gigantic furnace, about three feet taller than you, sits in the middle of the stone room. To the right, a metal tube with wheat stuck to the end points towards the burning fire. To the left, water sits above a different heater, seemingly powered by the furnace itself, that dispels steam into a vent. You step into the stone room, but your feet do not touch rock- instead, they find themselves on top of sturdy, see-through plastic. Below is a miniature of the city, with light on top of each building, all green.
Could this be the Scarlet Dragon? Just a furnace that misfired occasionally? You step closer to the contraption- it's become quite hot though, so you don't get too close. That's when you notice a door to the right of where the water comes in. On it, there is a tacked-on sign that reads MAINTENANCE.