Title is pretty obvious but I'll explain it anyway;
An event that would set the target (player) invincible for a period if time (max about 10 seconds or so)
This would make the player immune to bullets, explosions(radius damage), zombies, etc..
IE. [ 0 ] onActivate - player - setInvincible[3]
And if there is one please link me since I couldn't find it my self.