This Seeking Tech guide will show you how to unlock the Don’t Touch the Sides trophy and achievement.
To get this, you need to “use a knife to remove a bullet.”
To get a bullet stuck in your body, you need to fight Volgin or The Boss. Wait until either of these two characters start shooting their gun and get hit intentionally.
If you see some red on Snake’s health bar, open the Cure menu. Afterwards, use the knife, disinfect, styptic and bandage to unlock this trophy and achievement.
Check out the video below if you are having any trouble: