If the Lizard dies, you are stuck on the lift forever. Can it be put back to the gargoyle placeable or something? (and if not, can it not hostile PCs for accidental AOE damage?)
Or just make the lizard immortal.
If you do that, and someone accidentally causes it to attack them, then they have to survive somehow without killing it until the lift has taken them up, don't they? That'd be disastrous.
That'd be no different from the other travel agents, from tram conductors to ship captains.