Someone with tactical training. Fire discipline in an actual firefight is tough particularly for the inexperienced. Nothing in their behavior would lead me to believe they weren’t anything other than street thugs.
With a faulty trigger assembly, you pull the trigger once and maybe 3-4 rounds go down range. The second time, maybe it’s just one round (as designed). That’s what it looked like to me.
Well if he had training he should have learned to put his magazine in properly. It fell out, which is why he switched weapons.