Could be future Minbari military lingo for "guns ready" (note that the humans just say that the cruiser's weapons are "hot"), but you're right, does seem a bit odd. What's maybe even more odd is that we're told numerous times that the human targeting scanners can't track Minbari ships, so it's pretty amazing they managed to hit this one, much less actually kill Dukhat. Human weapons don't seem to be that effective against Minbari ships for the entire rest of the war, apart from the nukes Sheridan uses against the Black Star.