Factual error: The marines' rifles are supposed to fire "standard armor-piercing rounds", which should have done way more damage than producing a few sparks on the frail sheet metal table in the med bay when Hudson shot the face-hugger threatening Newt. "Standard AP rounds" would have pulverized the table and created a huge hole in the wall behind it.
Factual error: Master Sergeant Alexander "Al" Apone U.S.M.C. ranking was wrong on his uniform. His uniform showed a U.S. Army Sergeant First Class rank. (You can see this when they were loading up on their APC.) The correct ranking should have been 3 chevrons up, crossed rifles in the middle, and 3 rockers on the bottom. *Yes, in the future, the ranking system could have changed.*
Chosen answer: Down in the tunnels, she is the soldier that says "Maybe they don't show up on infrared at all." and is then grabbed and hoisted to the ceiling by an Alien, discharging her flamethrower and killing the other Marine. Later, Hudson says "The Sarge and Deitrich (the female medic) aren't dead. Their signs are real low but they ain't dead." So she was cocooned and played host for new aliens.
Grumpy Scot