As a ninja salvager, the correct answer is either to ignore me, or salvage as you go. If you do your mission with one or two other buddies salvaging while you shoot, there's relatively little I can do. Except race you for the mission item you need to complete the mission. That just never gets old. The item will either show up on contracts soon, or I might have a change of heart and jettison it.
Leaving the mission to get me NPC aggro may or may not work. Counter-intuitively, the small NPCs are the most dangerous to me, since they can actually hit my 1500km/s cheapo ship, and they can point me. If you leave me in a room with 12 battleships, I'll speed tank them without trying, and I'll simply keep salvaging/looting your mission until you return.
Salvaging/looting makes decent ISK, so blue-ing the wrecks makes me a little sad, but not enough to stop me.
Shooting the wrecks basically forces me to stay to make sure you shoot everything. I'll try to race you and loot from your containers if I can, since you're already shooting at things you shouldn't, which might indicate a level of frustration conducive to bad decision-making.
If you pop my ship (which isn't hard, a t1-fit destroyer could alpha it), you probably shouldn't stay in your mission, unless you happen to be missioning with a passive tank pvp-fit ship. Either that, or have some corp-mates on standby, and play the bait ship.
If you decide to leave, don't assume that you'll be safe coming back after 15 minutes. Aggro can and will be extended, thanks to the many wrecks in your mission.
Good luck.