I agree . If execution must occur, a full firing squad is best. I have heard of electrocution attempts where it took up to three times to kill them dead.Not a job I would ever want though. With a firing squad, it is unclear who shot the killing bullet.
nearly 30 years ago when I took an Industrial Electricity course at a state Voc/Tech there was a book in the class that told how the chair was made and the procedure of execution. The execution is a three step procedure with varying voltages for three specific periods of time. It basically cooks the persons brain. The first initial would likely render then unconscious.