or do one that would fit. Someone who's a us marshal or deputy us marshal. The type who if someone is being held hostage has no problem shooting through the hostage's upper chest to get they guy holding them hostage. The most he'd say if the hostage complained would be, "I missed all your vital organs, got the bad guy. The doc can patch you up. if none is available then my gun barrel can cauterize the wound, free of charge."
Someone who is a good guy, but only by the barest margin. That type seems the only one that would fit in. not the 2 that I came up with earlier. Sad to say.
got an idea about the gun barrel cauterize the wound from the pathfinder gunslinger class. They can do that. Stop someone bleeding by firing of a shot, if they have not the round or so before, and cauterize the wound with their gun. They can also open any lock by shooting it, and other things.
If the wagon broke down John would just do like I've seen on the 6 million dollar man. Not sure if the bionic woman did it. I'm sure they may have. John, like steve austin, would just hold up the end of the wagon (or car) while the other person replaces the wheel, Either oscar goldman or in this case Jack.