Close Call
From Halopedia, the Halo wiki
Close Call is a multiplayer medal in Halo: Reach. It is awarded when a player kills an opponent when he/she has no shields and has one health bar. Most players die once this medal has been received as the player is extremely vulnerable to enemy fire once it has been acquired. In the Halo Reach Beta, the announcer verbally announced the medal but not in the final game.