Complex sentence: Just as Pryor is helping him in the release cord from his harness becomes caught in the jagged metal surrounding the hole in the cockpit and as he climbs in his harness is released from the tether and he falls to his death.
Split into simpler sentences: Just as Pryor is helping him in, the release cord from his harness becomes caught in the jagged metal surrounding the hole in the cockpit. As he climbs in, his harness is released from the tether and he falls to his death.