Oh Sorry I misunderstood which one you were talking about. Yea that does sound like a strange setup, sorry I can't help you any on that one.... curious to see what others might suggest here....

I believe that to be an emergency exit hatch. It should be weatherproof. The one on my SunLite is framed like a roof vent, and has a crank up cover like a roof vent, but the screen and vent is on a hinged frame with a quick latch, which once unlatched the whole thing swings open to the outside so you could crawl out in case of fire I suppose. It is solid enough to hold in place but the frame is plastic and aluminum and the latch plastic so if you needed you could bust it out in a hurry.