Revive's can be gained in three different ways throughout the game. You can gain them in the pachinko mini-game, gather them during a wave from a present drop, or you can buy them with gems. For this achievement, I would recommend waiting until you find one during a wave, or get lucky and win one randomly in a game of pachinko (check "You are winner hahaha" on how to get pachinko balls). Once you die, you will be given the option to revive if you have any revives in your inventory. Revives come in very useful during the later waves, so it might be best to save them and use them when you actually need them instead of dying on an earlier level just to get this achievement early.