The actor who plays Major Kearney (Aaron Pearl) in this episode also played the young General Hammond in Season 2's 1969 (1999).
It has been very well established that two discharge-strikes from a Zat will kill someone, but none of the Stargate series report how much time must pass between two strikes before the second one effectively doesn't count as "a second discharge" and won't be lethal. In this episode, Daniel is hit twice, roughly 7 days apart showing that 7 days is apparently a sufficient recovery period from the first strike. The two strikes rule may also be a generalisation, i.e., they will kill most people.