Later, he will say it was a calculated choice, that he looked at the odds and looked at the clones and decided that better the Jedi he didn't know than the Sith he did. This is, as it happens, a bare faced lie. (or: A Sith Lord realises, abruptly and rather late, that war means casualties, and decides that the great Jedi genocide plan can go fuck itself.)

Obi-wan Kenobi was chosen by a Master when he was a few months shy of his tenth birthday. Twenty plus years later, the galaxy as a whole has rather a lot of cause to regret that. (The longer the war drags on, the more Qui-gon Jinn finds to question; about himself, about the events of history, and about the Sith Lord who was once Jedi Knight Obi-wan Kenobi.)

The Jedi were never meant to fight in war. They still aren’t meant to. But that’s what they’re doing, and that results in almost every single Jedi reaching for the Dark Side unintentionally at one point or another, results in every Jedi Falling, losing the parts of themselves that are kind and good. Except for the vod’e noticed when they started to Fall, and decided that they weren’t going to let it happen—and it turns out, you can’t really Fall if you have people to Catch you. Force-null or not, the vod’e figure out how to pull their Jetiise back into the Light, and do so as many times as is needed. General Kenobi is one of the last to start Falling for their first time.