I have a simple game in production and I am confused that when the player shoots and their bullets left is equal to zero it removes the enemy movie clip.

Heres a link to the problem:http://www.flash-online-games.co.uk/game.swf

As you can see when the ammo bar hits 1 the enemy (floating guy) is removed.
I have checked for conflicting variables and I have no removeMovieClip function in any part of the project.

I know this is a shot in the dark but any Ideas on why this would be happening would be great?!
Thanks