vamp cant be hit by gunfire during his special jumps, only inbetween the jumps theres a small timeframe in which he can get shot, so its always nice to spam his l1 + and forward "jump" to get close to the enemy, when the jump touches the enemy it also throws him down, then just press x to get in crouch position and knife otherwise you will be too high. This almost guarantees an kill if you are not surrounded, combine this with auto aim and hes one of the best unique chars in cqc u can get