John Carpenter's Tales of Science Fiction: The Standoff

At Tattersall Prison, a max-lock for the baddest of the bad, a fireball from the sky turns the night shift into a nightmare -- trapping guards and cons on the inside, cops on the outside, and escapees in-between... all of them threatened by a hideous alien invader which needs nice, warm human bodies in which to incubate. Now the clock is ticking and there's an invasion to be stopped.