Onew hurt his ankle so he couldn't do the dancing for the MV.  He did dance later in live stages tho after getting better

All 5 of them are in the MV, but there are a few dancing scenes that are missing Onew because of an ankle injury he sustained during a concert.

I'm currently on a SHINee binge and I finally found a place to ask a question I've wondered about for ages: who is missing and why? I know it's not Key or Jonghyun because we have close ups of them during the dancing scene, but I can't figure out who it is.

Missing Member In SHINee's 1 Of 1 Music Video?