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During the show, the two actors battled it out against each other through a quick quiz. On one question, they had to guess what the given hand gesture meant and was later revealed to signal a "crazy person". Lee Kwang Soo ended up guessing the correct answer which caused Jeon So Min to fall behind. 

The actress said, "Why're you keep shouting the answers out loud without the producer's permission? He never called your name." She then turned her attention to the producer next, "How come you're not pointing out this kind of unfairness?" As she continued to complain, Lee Kwang Soo said, "How much do I need to continue to match you? How much more do I have to be considerate towards you?" 

The two continued to bicker with each other until they ended up using the hand gesture they just learned to call one another a "crazy person" and made them burst out into laughter. Yang Se Chan who was watching this joked, "Both of them are out of their minds."

Did you enjoy 'Running Man' this week?