Either that, or the potions + namtars ward is simply too brutal to believe.
Best case scenario without accounting for passive dodge chance:
* 1 DP from CYDSTEPP (free hit)
* 1 DP from Namtar's Ward (free hit)
* 1 DP from badge of courage (free hit)
* Prepped GETINDARE dodge (free hit)
* Quicksilver dodge (free hit)
* Reflex potion double-strike (free hit)
* Strength potion x2 (massive damage single-hit)
* first strike finisher (last hit)
That's 7 hits plus the extra power from strength potion. I doubt he had the badge of courage, but he could have gotten lucky and gotten a spontaneous dodge somewhere in that combo. With all the other stuff there a 5th level zombie kill actually sounds fairly straightforward.