When you activate Doomfist's ultimate ability, Meteor Strike, you jump up into the sky, enter a targeting view for a few seconds, then smash back down.
While you're targeting the ability, your character is very high up — perhaps even above the usual height limit of the map. It would be hard to an enemy to target you in that brief time, but a skilled sniper might be able to pull it off. Would it be possible for them to save their team?
Is Doomfist invulnerable when he's in the sky targeting his ability? Can you stop the ultimate by killing him at that point? What about using an interrupting ability such as Ana's Sleep Dart?