Undoubtedly, it has happened to most before that they kill a Sova who is about to ult and you just hear: "NOWHE-" or a Jett who ults, but you shut her down before she can finish her sentence.

Not only does the cutting off make for some comedic timing, but a little banter from the agent who kills the ulting agent is fun to have. Something like:

Jett: "Watch thi-"

Killjoy one-taps her

Killjoy: "Those knives aren't going anywhere!"

Or:

Raze: "Here comes the -"

Brimstone fires 99 odin bullets

Brimstone: "Raze! No partying on the battlefield"

(Edit: spelling and post structure)