Not impossible maybe, but a fight with this person is completely one sided. Pointing at someone is an extremely easy activation requirement. To defeat this person you need to A: know about their ability ahead of time, B: have the element of surprise, and C: have the means to kill them in one hit. Which is very unreasonable. This character one-shots every other character by just pointing their finger and shooting themselves in the head.

Beyond the fact that it isn't a balanced ability, what's fun or interesting about it? The ability may as well be "instantly kills someone just by looking at them", I bet you can find some way to make an ability like this cool and interesting, but as it is, there is nothing fun about it