This whole situation spans over a longer time frame than shown.
You and your friends alongside some other not so cool people decided to turn your back on me when I needed help, I also learned you helped the not so cool people do it. It was especially uncool when we had interacted previously and were thought to be alright people. I questioned why you let it happen and as a response I was locked out of the apartment I previously had access to, and ignored by everyone else.
You brought this entire thing on yourselves as you caused a significant loss on my end by simply ignoring me. (Pots, drugs, money, etc)
It doesn't take a rocket scientist to put 1 and 1 together and tell that I wasn't too pleased with that.
You were based together in P4, I was downstairs in P1 with one of your friends. Again, not a very cool thing to let your friends get raided, is it? Not to mention house the people who did it.
The plan was simply to assassinate you by blowing the barricades off and sniping you @Yasha through the windows, plan got more complicated as the barricades didn't fall properly and kept obscuring my view, so I waited as I was still not detected, and waited, and waited, no movement so I changed locations and waited for another opportunity, that's where this specific situation comes into play.
I'll admit that in the heat of the moment (I'm still not used to criminal activity after being a cop main, keep this in mind) killing you @edik354 was unnecessary and I could have escaped pretty much unknown to you after switching cars. But this is the thought process you have afterwards, and I realized that immediately after that chasing after you was a poor decision. My original plan was scrapped as it wasn't valid anymore and I had to improvise. Again, I'm not great at this.
My mind was rushing through a few hundred possibilities about the situation as I was doing this, I think the crucial part of why I didn't leave after shooting Yasha was my mind thinking there were still witnesses. It was a poorly executed assassination, that's all I can say.
That's my side of the story.