As a side note, and NOT about this specific incident (merely related in terms of hardware) i personally believe that without mitigating circumstances if someone else is the aggressor, and is pointing a taser at me, and I have a firearm, I would consider the taser to be grave harm and a potentially lethal threat (less lethal just means not invariably so, and we know people have died from it, let alone the fact they could taser you, then walk up and kill you), and that would be sufficient for the potentiality part of the SD aspect...if within 10-15ft, then also opportunity.
What do you think? Does DEFINED less lethal aggressor mean ok lethal response?
What if they are 30ft away? Is it a 21ft + taser range? (If they are pointing and you aren't drawn)?
I wonder if there is case history on such an aspect?