You keep at it

You bend down, take a deep breath, and start to struggle again in the straitjacket, with all your available strength. You move your body back and forth vehemently, twisting and jerking your limbs in every feasible direction. But there is simply nothing you can do.

Shit! You think to yourself. The people who built this place knew precisely what to account for regarding their captives. So no, you are not getting out of this cell. No matter what you are trying to do.