Since we're talking about the US, that is never how a firing squad execution was done.
When being executed by a fire squad, a deflector is placed over the heart so the squad can aim at it.
Completely incorrect.
Only one of the squads guns is armed with live ammunition, so there is 1 bullet fired into the heart.
Common myth. In actuality only one of the squad members used blanks, not that it would make a difference to the shooters "guilt" anyway, since the significant differences in the recoil would be an instant giveaway.
It takes around 7 minutes for a person shot by a firing squad to die.
Not painful. Yeah.
Incorrect. They aimed for the chest area and heart, and traditionally it took between 1-3 minutes to die, with the body in shock.
With lethal injection the victim is injected with three different drugs and there are flaws with the administration of each.
Firstly, an anesthetic called sodium thiopental, is injected into the victim's vein, next, pancuronium bromide, which paralyzes voluntary muscles, then potassium chloride is injected, which stops the heart.
If thiopental fails to cause anesthesia and then the potassium chloride is injected, the victim could die through asphyxiation with his/her veins completely on fire and not being able to alert anyone.
The current lethal injection process can take anywhere between 10-15 minutes for the victim to die. But, they're still using the same process concocted in 1977 by a medical examiner by the name of Jay Chapman.