"If you can take a bullet, you can handle a few stitches."
Most severe injuries occur far from a facility that could treat them, and in the fetid muck of the battlefield even minor wounds may be a death sentence. Luckily the soldier is well-trained in the use of their standard-issue medical kit. They may stabilize even the most severe injuries with a little gauze and some no-anesthetic stitching. Furthermore, the treated wounds of their comrades never get infected.
Passive, always in effect.