Would you explain which ship is carrying such a helicopter? The Russian Navy doesn’t have any.
Any ship with a flat deck.
The Mi-8 has about a 400 NM range without external auxiliary fuel cells. So, even more with this cells.
Snake Island is about 180 miles west of Crimea. Which makes that flight and mission absolutely doable from Russian- controlled Crimea.
So I’ve given you two absolutely plausible scenarios now.