Top producer Shinsadong Tiger revealed that Kwanghee had rejected the song, "Shock".

On the November 20th episode of 'Strong Heart', Kwanghee complained to Shinsadong Tiger and said, "We're close, but how come you don't give us a song?". Shinsadong Tiger then answered, "I've given it to you before". Kwanghee still complained, "I heard the song he gave us back then, but it was so bad I gave it back to you after listening to it for 10 seconds. I wondered how he could give us that song. I thought he was looking down at us. What was that song again?"

Shinsadong Tiger shocked everyone when he revealed, "That song was B2ST's "Shock"." If Kwanghee had accepted the song, ZE:A could have sung the hit song instead of B2ST. Shinsadong Tiger continued, "I played the demo on the phone, but he rejected it right away. He should have listened until the last part of the track, but he told me to turn it off after just 10 seconds."