Escaping your RV in the event of a fire

I have a Fleetwood 'C'. The escape hatch is the rear window over the bed, but it is NOT hinged. You open the handles and the window falls out, probably for a faster exit. I've heard that they're impossible re-seal. OTOH, if you needed to use the hatch, I don't imagine that there would be a frame left to hold it.
If you have a setup like this, fight the urge to see if it works.