'And... we're out!'
[Get back here, you little pest!]
'OH COME ON!'
Once Zhen Liu and the stone zako he was instructing had determined that the vent to the furnace room was their only way out, they committed to just travelling up the thing regardless of where it wound up.
Zhen Liu had initially hoped it was a straightforward run to the top with very minimal detours involved, but that wasn't the case in the slightest.
For whatever dumb reason, the climb out of the exhaust vent was winding, long and took the occasional unexpected turn. On the plus side, the smoke got visibly thinner as Zhen Liu climbed further up the exhaust due to the presence of several smaller exhaust vents perforating the sides of the main one.
They were also fairly small, though, which made it nigh impossible for the zako to wriggle its stone body through.
Evidently, that was going to be the least of his problems.