If you kill the crew attempting to get-in. Once you have chosen the get-in option, you will then get rid of the dead body to take place.

The corpse, stay just under the helicopter, stuck between cokpit and metal bars.

This cause the helicopter to take quick and heavy damages, as if the corpse was boxing the cokpit, rebounding between ground and cokpit.

So, the helicopter is useless cause fully damaged (engine, ins, hull).