Okay , I'll try to describe it as easy as possible in steps ...
1 - Create a Variable GameEnded that starts at the value of 0
2 - In the event that triggers the end of the game , add this action : Set GameEnded to 1
3 - In the events that adds 1 to ShotsFired , add this condition : If GameEnded = 0
That's all !
Cheers ...Wouldn't that set the shots fired back to zero?