As far as those two being coked up and doing the hit on a whim???
Lets say they wanted to settle an old beef and they bolted home and haphazardly grabbed a gun and a ski mask then rushed over to the crime scene thinking they could clip him and take off...that would still be an unplanned and somewhat random hit. Also, everyone keeps bringing up Grande and perhaps he never had anything to do with it.
That sounds plausible to me.