I respectfully, fully, 100%, disagree with you. We aren't talking about a flying boat that is unable to stop it's decent, we're talking about a little-bird, a helicopter known and loved for its FAST collective changes mid flight. Hatchback Sport's driving and A helo landing; They are Apples and Oranges
If warning was given, and then they continued to land; they may as well have hit the sirens. Full on initiation. 5 seconds, and then they die. Rotor, pilot getting shot - I'd argue it doesn't matter. It's been stated Over and Over, warning shots ARE the start of initiation (systematically speaking).
My tip - Make sure they Know the Shots are a warning, and a start of Role Play (Space them out, don't for the love of God hit the heli).. Hell, yell in direct at the same time! They may get the point.