The relaxing scenes at the end feel more than just a bit foreboding considering what the lion did to thistle at the start, they're all just blissfully unaware of the fact that after a while the lion will be wanting to do the exact same thing to them.
laios really is too trusting, but there really wasn't any other choice here than trying to talk it out with thistle, killing him would mean that he couldn't revive his friends nor unseal the lion. but the problem is that thistle is too batshit insane for talking to work