Tryndamere dying in ult [Gameplay]

Now I don't exactly what caused it to happen, but basically Kha'Zix (using the death blossom skin) managed to kill me after I had used my ultimate.

Here is a video better describing the situation: http://plays.tv/video/57008bf69a26e1242b/turns-out-tryndamere-is-a-fraud?from=user