Hmmm. Have we figured out if photorps already come with antimatter? Or are they loaded with antimatter while in the torpedo tubes right before firing?
On one hand, preloaded torpedos that are damaged would be catastrophic, but on the other hand a dedicated antimatter "line" from the storage pods to the torpedo tubes presents a vulnerability that could be exploited.
, I am inclined to think the Klingon gunner just got "lucky" and hit the ship's M/AM reactor on the first shot.