There was no vacancy between the water and the stone which shut down upon it.

The outlet was like an open faucet to a full barrel.

The escaping fluid filled up all the space at command.
No one can live long without air.

A few seconds of suspended respiration is fatal to the strongest swimmer.

If the distance traveled by Mickey, when he should attempt to dive or float through to the outer world, should prove a trifle too long, the stream would cast out a dead man instead of a live one.
But he was a person of thorough grit, and before he would consent to see himself and Fred imprisoned in this cavern, he would make the attempt, perilous as it was.
Was there no other way of escape?
Was there not some opening which had been used by those who had entered this cave ahead of him?
Or was it possible that the imprisoning walls were to thin and shell-like in some places that there was a means of forcing their way out?
Or was there no plan of climbing up the side of the prison and reaching an opening in the roof, through which they could clamber to safety?
These and other thoughts were surging through the mind of Mickey O'Rooney, when an exclamation from Fred caused him to turn his head.