Hey guys! first post here, just thought I would contribute my two lincolns... Some great theories, but heres an idea for the slow assimilation theory, look at it like this. The body is composed of TRILLIONS of individual cells, assimilation through that process would take a numerous amount of time right? wrong, from a cellular perspective, every assimilated cell then moves on to assimilate another. INITIALLY this is very slow, but it soon reaches an exponential rate, moving RAPIDLY throughout the body. This could possibly explain blair's fate. That theory being plausible, I do not support it in Norris's case. I believe Norris was replicated to a tee, including his heart problems. I believe his body reacted as it would normally, he simply had an attack and the thing (being in the room with humans) had no choice but to react humanly to it, as shrugging it off (with the other members knowledge of Norris's heart problem) would immediately blow his disguise and put the thing in a potentially bad situation. I believe the thing intended to wait to act till it was either A. discarded by burial or whatnot or B. left alone on the slab and could escape. We have to remember the thing relies on self preservation, it didn't WANT to fight. Another point that could possibly be brought up is, well why couldn't Norris's body (under the things control) just play dead and ignore the shocks from the defib and be discarded? Well much like the blood scene, we can only assume the shocking from the defib pissed the thing off and it reacted out of self defense. We can safely say norris-thing did NOT want to be discovered, but unfortunately the host was riddled with flaws, and it consequently suffered from those same problems while in human form ultimately leading to its discovery and demise.

I believe he had a heart attack in order to easily kill the Doc and possibly a few others. But those Things are too damn slow and only manage to kill like one person every time they show up, and still ten people got killed...

I got the impression that the thing faked a heart attack. There was Mac with a fist full of dynamite, and a serious attitude problem. So it figures "Fake a heart attack, maybe the focus will be on saving their friend and the guy with the explosives will either be distracted, or at least I might be removed from harms way and be taken to the infirmary". Basically it decided to take a chance on playing dead, rather than take a chance on being blown up / burned up. On the table it felt backed into a corner, so it attacked as a last resort. Pretty much it was a case of "rushing the gun man". Stand there and get shot, or make a move and possibly get shot.

Not sure if this has already been pointed out, but 'Norris' emits a couple of high-pitched whines just before the Doc uses the paddles for the second time. This seems to suggest that 'Norris' was fully conscious prior to biting off the Doc's hands although he may have been, at least partially, paralyzed. Alternatively, these noises could have been a consequence of the significant alterations just made to the contents of his chest cavity. XidiouX

I'm convinced Norris wasn't consciously the thing because of how he acted prior to MacCready's entrance into the supply room. He appeared to be very concerned with what was going on and actually tried to keep everyone from fighting each other after Window's loses his temper with Palmer. I believe he says something along the lines of: "Stop you guys! It's playing us against each other!". Also, lets take into consideration that his entire body wasn't used in his "thing-out" morph; I actually think the distorted, mini-Norris thing that launched from his chest was actually a sign of an incomplete take over.