Yeah, some Goal other then slaugther would be nice. Like, disable some device on the other side of the map, or boss fight. Also, maybe more varied enemies, but good to keep them to their role. Like CA snipers/Mutant melee with 1000 hp/Ranger armor big gunners, so they can be recognized.
Other then that, i dont think there can be much more made to improve this event. This event is all out based on combat system of fonline, and it is pretty simple one, and so it is hard to make an event based on it that is not pretty simple aswell or in a bit more straight forward language braindead. All you did was, reload, shot, reload, shot, get more ammo, reload, shot, reload, shot, get more ammo... and so for those 1-2 hours.
Like SurfSolar said, maybe some backround/story or goal/mission.