Innocent question: What part of the body does the firing squad aim at?
Once again...
Though a firing squad might be emotionally satisfying, all crap like this does is muddy the issues. Same with electrocution, and most other methods. All you need to perform an execution is an air-tight room with room for a gurney, so the criminal can be strapped down. Pump in pure nitrogen while evacuating the air from the room. Once you’re at about a 99% nitrogen atmosphere, the condemned is going to die within just a few minutes.
Set a timer, and when it dings at the 15 minute mark, you pump normal air into the room and dump the nitrogen outside. This is easy, simple, cheap, and there are no poisons, or other crap that can get in the way. The condemned will be dead and probably won’t have any idea when it happened.
If the state is going to execute people, just freaking do it without all the circus crap that currently clouds the issues.