In fact the Earths atmospheric pressure is tremendoes. We just don't feel it. Our blood pressure is what keeps us from being crushed. Blood pressure is formed when your blood fills enough to "push" out on the inside of your body. In order for the pressure to sustain against the atmosphere, there would have to take a lot of blood.
It looked like it, but to me it also looked like it cut his head off because i was able to see his torso, it didn't look like it was cut in half, more like the head
~Another Female on the Site~ ~IN SPACE NO ONE CAN HEAR YOU SCREAM~
let me see if i can clarify a little confusion becuase i do remeber that part. first the yautja fired his plasma caster at keyes, but you can't really tell that he got hit, the camera goes off the another location. we have to assume keyes was able to dodge the plasma charge yet was still burned from the intial blast as it hit the wall behind him and set off a large plume of sparks. then later, the yautja launched the smart disk and it went through several cattle cadavers and eventually through keyes' abdomen. like predatress said, it was a flop that only keyes' body from the stomack down fell to the floor and only that, no other parts of him fell to the floor. i'm not sure how they could have missed that when they made the movie but oh well. hope it helps