Quote Originally Posted by Hyperia View Post
Zenos died because he was trying to echo jump into the warrior of lights body. It was not possible because our echo is original and stronger than his. The crystals of light probably provided additional protection from echo jump body stealing.
That's an interesting take on what Zenos was trying to achieve by killing himself, which might fit with whatever he said at the time (I can't go and check right now, though I remember there was some kind of theatrical metaphor to it) but definitely doesn't line up with what he says in 4.3.

KATANA-WIELDING SOLDIER
There upon the stage I stood, prepared to take my final bow, only to find that the finale was but an intermission...
He thought it was the end, and that he was "leaving the stage" on his own terms - only to find that it wasn't over at all.

My own best guess is that he had every intent and expectation of death at that point, only to find himself a still-conscious soul trapped inside a physically dead body, most likely due to some effect of his artificial Echo.

An alternate suggestion I've seen is that it's something to do with the katana he picked up from the Kojin, which seems to be some kind of magical relic but it never gets expanded upon within the game so far. Possibly that his soul might be trapped in the sword (via some kind of inadvertent blood ritual by killing himself with it) and then the unfortunate Elezen soldier comes along and picks it up...