Yes, it is. He had been called in to speak with UN representatives about why they should maintain the League's funding. He had already been using his mind control to try and make them more amenable to the idea, resulting in the usual trickling nosebleed.
The next page had another beat... and then a *SPLORT!* as a huge gout of blood shoots out of his nose.
(Personally, I still say the Perfect Moment for Booster and Beetle has to be the one a bit earlier in the story when they realize what they've caused by hiding all the Oreos^WChocos within a one-mile radius of the embassy. "We're gonna get yelled at, aren't we?" "Big time.")