The deformed and mutated Fifield returns to the Prometheus , where he attacks the crew and murders several members before he is killed .
Fifield decapitates one , and its corrosive blood melts his helmet .
The deformed and mutated Fifield returns to the Prometheus , where Fifield attacks the crew and murders several members before Fifield is killed .
Fifield decapitates one , and its corrosive blood melts his helmet .