Maneuver: Move to Garr (2 strain)
Action: Heal Garr's Crit
Curing Garr's Critical Injury (Medicine): 2eP+2eA+1eD 1 success, 2 advantage
So that should heal the critical and heal Garr 1 wound + 2 stress. I'll stick around next turn and try to heal him more traditionally with a stimpack.