Manic Monday Bonus--How Do You Stop A Rhino From Charging?

Let's check in again with Marga, who has been thrown into the "rhino pit":

Damn, and the evil Dr. Cruor had spent so much money constructing a rhino pit as a death trap, too!!

But wait...

You, the story never does explain how the rhino got out of the pit...

From Weird Comics #16 (1941)