It was a targeted killing with an unknown motive as of yet, one in which the killer and victims knew each other. The killer had a prior criminal record including violent crimes. While you may argue that anyone who kills someone else in a non-self-defense situation fits the definition of "mad", this does seem to be different from the "madman with a gun" scenario originally hypothesized.
You are correct in my opinion.
I originally posted this with the scant information that was available at the time....However my point is training for this scenario when it escalates to someone surprising you in public by whipping out a pistol and blasting away is pointless. The moment the gun is drawn and fired you're in God's hands. There are somethings you can do to raise your odds of survival to be sure...and I not really sure if Martial Arts will apply though Martial Resolve and the will to live may help.