you would think a cc instructor would be packing something with more muscle than say a 22?
however other smaller cal autos are popular cc that may not have put down power.
iirc, from stories back in the day druggies on PCP were hard to put down on the first shot.
adrenaline rush could keep um getting back up?
he could have been wearing a vest?
Look on the youtube for “dr’s view of gunshot wounds”. It’s quite gruesome, but it will also answer some of your questions, especially regarding how people can keep going after being hit.
Quite educational.