Under Pennsylvania law, if these “stun gun bandits” robbed a Starbucks with a gun, you’d be legally justified in shooting them. But they are robbing with a stun gun, which is not deadly force. In many states, you can use deadly force to stop a forcible felony, and robbery counts. Pennsylvania is not one of those states, however.
Could you claim self-defense for the use of deadly force if you had a pacemaker or bad heart, and were threatened with a taser? More importantly, if you’re carrying a firearm, and are threatened with a taser, can you claim self-defense because they could use the taser to disarm you?
If it were me, I’d probably spray them. But I’m not sure that’s the smart move. I tend to think the use of deadly force to stop a forcible felony is the correct standard. That standard does have its roots in common law. If you’re committing a robbery, you’re taking your life into your hands. No matter what the instrument. That seems, to me, to be the right balance.