Continuity mistake: In flashback, we see the one-armed man kill Helen Kimble by striking her with a heavy lamp. All through the earlier seasons, though, we were repeatedly told that Helen had been strangled. (00:28:50)
Continuity mistake: When the lab equipment shorts out after the earthquake, the unconscious Major Brothers is lying with his head propped up against the wall. But when Hamilton reaches him in the next shot, he's suddenly lying flat and is nowhere near the wall. (00:21:45)