In the 1983 film "Superman III", Superman - while infected by synthetic kryptonite - ends up fighting his normal "good" personality in the form of Clark Kent. The scene is highly symbolic in nature, but one thing always confuses me regarding it. About halfway through the fight, both of them are on a conveyor belt leading to a metal compactor. Dark Superman is apparently winning, beating on Clark with a bumper, and then he suddenly becomes weak and drops the bumper before staggering:
No apparent reason is given, and it doesn't happen at any other time during the fight. I've seen it suggested that he grew weaker because the Clark persona was standing up to him... but at this point in the fight, the "evil" side was winning.
Has anyone involved with the film commented on or explained this sudden weakness?