when i said 'any car', i meant any thing that you can drive. this means helis, boats, anything. for that helicopter mission, you are placed in turret mode at a slight offset to the left. and that specific opcode is used.  
if this opcode was to be used to place a player in turret mode on a heli with the current core, there is a big possibility the person will get chopped into oblivian due to lag, and also the shooting would (still) not be synced, however the players position would always remain at a certain offset to wherever that helicopter is, whether a player is driving it or not.