You had noticed some odd details about Keegan. He didn't always smell the greatest no matter what he used, never was seen actually eating food, and the enemies he took down were oddly mangled.

You were on an op with him, moving stealthily. Something went wrong and the enemies knew where you were. A bullet hit you in the shin and Keegan crouched in front of you, to protect you. Suddenly, he flopped over as a bullet went into his chest. You went to radio that he was down, except he just got up.