I think you can only load up 3 or 4 shots. So If you can avoid a few of them the opponent remaining weaponry strength is compromised ? Maybe I should have stuck around.
Torpedoes are kind of a one and done weapon. They're extremely devastating but each launcher can only hold one so once it's fired that's an entire weapons system offline.
I think there's two different sizes where bigger ones get a single reload but that's kind of it. Unless there's an ammo effect on the engineers Torps are best used as big ship hunters and you have to hope they hit. If they miss, you are in effect, screwed.
If they hit though, the other guy is probably about to have a very bad day.
You can lock onto torpedoes just like you can a ship and shoot them down. Alternatively ECM and any method used to break missile locks can counter them. Thirdly you can just evade them until they run down the timer and prematurely explode. Smaller ships can evade them pretty well so larger gunship class ships need to pick a tactic while Frigate sized ships better be packing smaller interceptor weapons and point defenses. SLF's can probably run screen against torps too.
So yes. Once volleyed he would have been compromised and would have had nothing to shoot you with.
But NPC's are notorious cheaters and may have their torp ammo count hacked.