It is evident that the beast has been struck with a flying piece of lead, and is about to fall under him.
The doctor says nothing, and hopes his absence may not be noticed by the flying column, but, as it happens, when the catastrophe does occur, all of them see it.
Fortunately John clears himself just in time, and reaches the ground in safety.

Lady Ruth pulls in her horse.
"You must not stop!" cries John; "urge your horses on--fly while you have time.

I hear them coming!" He tries to start Lady Ruth's nag, but she pulls on the lines.
"I decline to run and leave you here, Doctor Chicago," she says, resolutely.
"But you must go," he declares.
"Nonsense!" breaks in Philander.

"Here's room for you, John.

Jump up." The young man sees that the quickest way to get them started is to obey, so he manages to reach the saddle in front of the professor, who clasps his arms about him and holds on.
This done, they clatter on again.
It soon becomes evident that their pursuers gain upon them rapidly, despite their best efforts.