Ashley asked me if Cat could save them. So here's my answer:
Gravity will accelerate large stones 32ft/s2
Which means in 1 second the boulders will accelerate to 32 ft/s So in the first second the boulders will have traveled 16 ft. They are 20 ft from the ground, but your heads are about 5. So in one second you could be struck by fallen boulders.
Ignoring acceleration, you can travel roughly 60ft in 6 seconds if you dash, Cat can go 120ft with her feline agiity.
So in one second, about 10 ft, Cat can get 20ft.
The affected area of the falling stones is roughly up to 15 ft. south.
If the ceiling falls Cat can escape if she runs with dash and feline agility.
