To defeat the level 4, Medical, Boss, when the fight starts run around the room, dodging its projectiles and shooting it in the head. It will not do much damage, but it helps. At certain times, it will stop and shoot a huge wave of projectiles at you. Try your best to get in between two projectiles to avoid it. Tip: When it is about to do it, it will wiggle its head around as if it is in pain. Watch out for this sign. Eventually it will kneel down and put a blue shield around its head and start healing itself. Quickly run over and throw a grenade into the hole in its shield to do lots of damage. If you do not, it will heal itself back to full health. Immediately after you do this, quickly back away as it will try to attack you with its claws. If you are low on health, you should get one of the three first aid kits at this point. This fight is going to get a lot tougher. Immediately after you do this, it will change its tactics. It will start shooting more projectiles more often and instead of shooting a wave of projectiles, it will emit a huge orange electrical beam from its mouth. Stay far away from it, as it will sap your health quickly if it hits you. The last thing it does is get out of the middle of the arena and roll around the room. It either rolls around near the center of the room or the far side of the room. Indicate which part its rolling around to avoid it. Keep repeating the strategy to bring down its health. When it is almost dead it will roll around and stop to reveal an opening. Throw a grenade into the opening to do damage. Eventually you will defeat it.