Is it possible the helicopter blew him down onto a slope and off the cliff? Might not have been a lot of wiggle room after exiting the helicopter.
Anything is possible. Accidents do happen to rescuers and victims alike. Sometimes there are “miracles” and sometimes the “chaos theory” applies. Your question is possible, depends on the height between the trooper and the helicopter. The closer the bird gets the more rotor-wash and thus potential for losing ones balance.