I didn't have sound so I may have missed something.
Yes, you did. Dave gave a reasonable advice: "Donīt do it."
I admit that my mind closed at the site of him voluntarily cutting himself. Doesn't seem like a wise choice to me, especially by guys that are supposed to be showing us what TO do.
Those guys are supposed to give a good show. Do not confuse that with showing what to do. Unfortunately each season has to be more spectacular than the one before. So expect the techniques to get less useful.
When I get past that, I'm left wondering: given the resources they had available, what were the other options to close up/protect a wound like that?
The wound was so shallow that it would not even require a suture (Iīve actually taken a cut like that from slipping with a straight razor). They had trouble to KEEP it bleeding. It will usually stop bleeding by itself in a couple of minutes - almost immediately if you apply a little pressure). Applying direct pressure is the proper way to deal with even more severe wounds.
The cauterizing by applying a generous amount of heat is supposed to cause plenty of dead tissue with an elevated risk of infection and long term damage. The original wound might not have left a scar - the burn probably will.
Apart from that it does not seem feasible at all.
- start the fire before getting injured - otherwise the uncontrolled bleeding might kill the injured before you get your chance to do so
- even with the small wound the powder got to wet to light - a live threating wound might well soak all of their gunpowder
- the pain from the burn may well cause a shock and generate a life threatening situation by itself
I would really recommend you to attend a first aid course. Itīs worth itīs money just for the confidence it gives you for dealing with medical emergencies. If you successfully apply the skills only once itīll be priceless.