While the stone was thick and tough, with enough acid applied to the mortal, he managed to do a lot of damage to it. Enough that, once he'd exhausted the vials and minor spells, Aurelia directed him to back away, then, with a bit of shapechanging magic applied, to increase strength and, more importantly, mass, stomped on the floor where he'd weakened it. Once, twice, and-- CRACK.<br/><br/>The stone gave way, as she tumbled backwards, revealing a staircase that's now rather smashed up, from the large stone, tumbling down it, but still more-or-less usable.<br/><br/>"After you," she said.