Here's my guess:
That shot where he extends his lightsaber is the closing shot of the series. He goes up against Sheev, and they don't show a fight because we know how that will end up, and they also don't need to show him being killed.
It also leaves room for some ambiguity regarding his fate, now that we know that being rescued from outside time is a possibility. Then, if he does show up in a later series, they can explain it then.
It also leaves room for some ambiguity regarding his fate, now that we know that being rescued from outside time is a possibility. Then, if he does show up in a later series, they can explain it then.