No you can't set number of kills. You can set razings score if you want.
I find this interesting:
QUOTE(dz187)
Yeah it's so it doesnt preserve
Yet:
QUOTE(dz187)
Preserve Trigger

Note that you do still need the switch with this particular method, even when you take off "Preserve trigger", to prevent multiple players acting on the same trigger.
With your latest method, dz, triggers are run one player at a time - so Player 1's triggers are checked, then Player 2's triggers, then Player 3's, and so on. Could this explain what is happening?
I suspect that you have triggers for each player which go along the lines of: "If my bunker dies, then give turret to player 7 and defeat me." Then if a player with higher number than you dies, then your "give me your turret" trigger fires before that player's "defeat me" trigger (since triggers are checked player by player), so you're trying to grab a turret from player 7 before it has been given to player 7.
To make sure that the "defeat me" trigger is always given enough time to fire before the "give me your turret" trigger fires, you can: (i) Insert a "Wait 0 milliseconds" action sometime before you give the turret, or (ii) Add the condition, "Player 7 commands at least 1 turret".
Veritaserum's method works if you change the conditions and actions to affect razings score rather than kills number, and bunkers are the only things that can give razings score. (Do turrets give razings score?) In this case, you still need some method such as mentioned above to make sure that (i) you can find which turret to give, and (ii) the trigger won't activate before another required trigger (such as the "defeat me" trigger) under a different player activates.
But your method should also work, if my hunch is correct.