I have been able to obtain more details regarding Brock Lesnar's tirade backstage at Extreme Rules this past Sunday.
Brock was informed on April 16th (while the majority of WWE the roster was overseas) that he would be going under to John Cena in their main event match at Extreme Rules. The way it was explained to Lesnar is that while he would be going under, Cena's victory would be a "fluke" and he'd come out looking like the stronger of the two workers. The aftermath would have been Cena being stretchered out of the building and taking some time off with Lesnar getting "suspended" the following night on Raw Supershow.
Prior to Cena going out for the match on Sunday, he was told to work the "smarks" after the match to make it look like a shoot. Once Lesnar got backstage after the match, he went to the monitor to watch Cena's promo (which is out of the ordinary for Lesnar as he hasn't been "engaged" in current WWE programs). However, as Cena was cutting the promo, Lesnar started to throw a tantrum backstage and went right for Marc Carano (one of John Laurinaitis' assistants). I'm told this in itself was funny because up until this point Lesnar had gone right over Carano's head for everything.
One of my sources with knowledge of the tantrum told me under the condition of anonymity that many feel it was a work on the boys and the Internet fans. This particular observer commented on the fact that had Lesnar not known about Cena's post-match promo he wouldn't have been watching the monitor backstage and certainly wouldn't have gone directly to Marc Carano.
The feeling is the entire thing was done to appear the company had gone behind Lesnar's back to make them appear in control when in reality, everyone feels WWE needs Brock more than he needs them. Brock was isolated from most of the workers backstage at Raw Supershow yesterday and if he was truly upset and the tirade wasn't a work, the opening segment of last night's show wouldn't have been as safe as it was.