With a howl of fright he felt himself plunging head downward more than thirty feet to the hard floor of the gym.

He was in a fair way of landing on his head, cracking his skull and breaking his neck.

Worse, in his sudden dread, he seemed to have lost control of his muscles.
"Turn! Land on your feet!" called Dave.
It all happened in a second.

Dave, brief as the instant was, realized that the other midshipman was not going to land on his feet.

In the same fleeting moment that Darrin called he hurled himself into position.
Straight down shot Jetson.