Plot holes in "All Fall Down" (S08E24) (spoilers?)

I know it's TV, but still...

The first person killed, was the victim of a single shot from a rifle through the kitchen window. Yet somehow, Calleigh was able to pull out the bullet from that same window with a pair of pliers. If it was in the window, how did she die from a rifle shot?

The guy who drowned. First of all, despite the weight of the fabric, I am SURE he could have lifted enough of it to get SOME air. Also, there was no barrier (other than a rope at the water's surface) between his lane and the next. So he could have easily moved to another lane that wasn't covered (since only his was). Also there appeared to be a several foot gap between each cover.

And lastly (and probably most importantly) we subsequently see a "4'" depth marker on the edge of the pool where he drowned. Guess he didn't think to merely stand up, lol.