He made the most tactically sound move even if it is high-risk. His impromptu hostage situation has essentially completely negated the enemy heroes because they're now forced to keep their attention on him while the highserk soldiers just go ham without having to deal with the BS heroes.
Another thing I found especially tragic from this chapter and the last one is walm doesn't really have the time to mourn his friends. He just has to get the fuck up, with his burned eye, broken fingers and charred bone and avenge them, because who else will?
I can see why the guy in the fort is so happy to see that blue flame, he legitimately just got a get-out-of-jail free card from losing despite having lost his most valuable units in the previous battle.
I'll always be sad when translation teams drop mangas because of official translations, I feel like there's something deeply human in there that's lost with official translations.