8. Get an Injection (As Many Times as You Want)
Not all shooters allow you to duck behind cover to heal up. Some require that you get injected by a teammate like in Brink or the Army of Two franchise.
There's almost no limit to this wonder drug. You can get injected multiple times in the same game with no side effects. Even better, your teammates never seem to run out of drugs!
Yes, we agree, it's weird that you never carry drugs for yourself.