So right now I'm up to season 6 in Stargate SG1, and I've noticed the main crew gets zapped with a zat'nik'tel A LOT. Shouldn't they be dead by now? I thought the second shot kills and the third causes the body to disappear. Did this change somewhere? Is there a period of time where if you don't get shot it wont kill you?
Director: The reality of the scene dictates there be dead aliens ... because you just killed them.
Head Writer: We could always go back to the way it was in the script.
Director: No we can't. We've already established that one shot stuns and two shots kills. Nick just shot everybody twice.
Martin: So three shots disintegrates them!
Director: Okay, you know what? I'm gonna pretend you didn't say that, because that is quite possibly the stupidest thing I've ever heard you say.
There's probably a residual charge or something left in the body after one shot which takes time to dissipate. Adding a second charge from another shot would then be too much for the body to take, and hence leads to death for the target.
Of course, this then opens up questions on things like body mass... shouldn't a bigger person be able to absorb more hits than a smaller person?
Also - I think the ridiculousness of the weapon was lampshaded in the Wormhole X-Treme episode ;)