The tunnel was already filling with smoke by the time they reached the end of it. Giving the shorter Ahayla a boost up to the drainage shoot. It was harder getting up than done the drain, as it's walls were slippery and slimy. Up above, black smoke poured out of the drain, as if chasing after the two women vengefully.
"Gather the remains of the door. Pile it against a wall," Allura told her apprentice before coughing.
Maybe the smell of the smoke would cover the smell of the drain on them? Going to the fireplace, she piled the firewood nearby in the hearth. Lighting the fire, she got it good and hot before grabbing another piece of wood and letting one end catch fire.