Accept the rubber vagina

A new nurse enters the room and gives you a well-lubed rubber vagina to masturbate and cum inside. She explains that soon, another nurse will come and you have to hold your semen inside the rubber device.

The nurse left the room and you are finally alone. This is a golden opportunity, you can check behind the machines, and perhaps this is the only chance to search for an escape.
However, you don't know what's going to happen if another nurse enters the room and you didn't cum.