In the recent shootings of unarmed black men in a San Diego suburb and in Tulsa, Oklahoma, the police officers who fired the fatal shots were accompanied by officers who simultaneously drew and fired their stun guns.

The different responses have raised questions about training. Those who have taken to the streets to protest police killings say the events represent proof that some officers are too quick to use their firearms.

Law enforcement experts say it's not that simple.

They say it is nearly impossible for police to switch between stun guns and fire arms when volatile situations escalate and that officers are human beings with unique perspectives who will react differently in the same situations.