Whats the deal with XAN? I can get ahead of him by about 4 kills then he starts wiping the floor with me? It seems like at first I can kill him with on rocket or flack blast. Once I get ahead by about 4 kills, It takes MUCH more to kill him. I even unloaded the entire rocket gun (multiload) at him and 2 hit him directly and the rest hit right next to him. HE DID NOT DIE! He also did not have shields at the time.