#4 Was initially brand exclusive
Elimination Chamber has always provided exciting moments that stood out and were talked about. When the chamber was first announced, its initial intent wasn't to use the talent from both Raw and SmackDown. When Eric Bischoff, who was the Raw General Manager at the time, announced the matchup, he stated the event would feature Raw talent that would compete at the Survivor Series in 2002.
However, despite originally being meant as a brand exclusive pay-per-view, it didn't remain that way. In 2006, at ECW's December to Dismember, the match was part of a different brand's event. After a few years, the match was exclusive to the No Way Out only pay per view. Since the structure offers ‘no way out', it appeared to make sense to be tied to this event only.