Weird Tryndamere Death

So as i was playing URF in the PBE as Tryndamere, I was spinning around, doin my thing. All of a sudden I encounter a Brand. So I walk up, and start spinning on him. I ulted to make sure I would get the kill, but even though it went on cooldown, and even though everyone said they heard the ult scream, I still died to the Thunderlords Proc. Riot, no more spaghetti please, I'm full. Also, this isn't that important, but numbers also appear on champions faces in the corner (sometimes) when you get in game.