Below Elephant Rock

Isaac nods and steps into the ring, taking hold of the two iron handles on his side.
Once all four handles are being gripped, the platform rattles as bricks shift and move, the platform raising slightly as channels slide into place around it, leading to the pool. Meanwhile, the statue slides forward towards them, the enormous urn slowly tipping towards them....
As it does, they'll have a moment to see the churning water inside of it. Isaac takes a deep breath before it comes crashing down on their heads.

How long can Isaac and Lucas stand gripping their spots under the force of a waterfall?