Make sure that when inverted and leaned forward toward the instrument panel you can still reach it.
I feel your escape will be to smash a small hole, insert device that made the small hole and chase any crack you can start.
Once it is about 18" long you will attempt to birth yourself through the crack.
If you have time, make a triangular hole from multiple starting holes connected.
I like camping axes with heavy wide blades. You may not have much room to swing.