Coldest moment in the show?

Which moment in the show is your favorite "coldest" moment? The particular scene that always gets me pumped up is when Aaron Hotchner arranged to be locked in with Chester Hardwick in a great, "I'm not locked in here with you, you're locked in here with me" moment. I just wish Dr. Reid hadn't stepped in and we got to see Hotchner whoop Hardwick.