Masked & Disguised

47 wasn't ready to get back to killing after retirement, so he decided to make somebody else do it for him.

OK, now to be serious, this tactic is not the hardest thing to reproduce but yeah - it is very luck based. The idea is to try to stay behind the target and use him as a human shield. In order to not let the target escape you have to keep him in place with single doses of anaesthetic and hide behind him while he is waking up. In the mean time, while he is on the ground, the guard will shoot at you of course, so the best solution is to stay behind the balcony wall. I got lucky in this scenario and the guard killed the Don very fast.
OK, now to explain why is a SA rank possible with all the mess that happened. That guard that I used for the tactic is actually the one I got a Close encounter from (in other words got spotted by). I didn't get any alerts and other CE's, since no other guard actually saw me or heard me and came to the crime scene. However, the guard did discover the dead body after he killed him himself :D - but for some reason that alert does NOT count in the end level statistic(no idea why). Normally that would mean no SA rank, since 1 CE and 1 Alert is Professinal rank. All the other warning signs you can see also don't count in the statistics. Show less