true, but that doesn't absolve her error either
the heroes are not very intelligence imho (in most manga they're hot headed overly justice type, NEVER the intelligence ones)
or maybe it's not like that, it's the mages who betray the dragon since the heroes ask it to hide her treasure, and they found it and sealed it, probably idk
I do like that his friends finally got to be unequivocally useful for once. Even if it was only through keeping the way out safe, it was something he hadn't considered and that could apparently have caused him actual troubles. (Since he was worn out from the fight and constantly drained by wanting to keep his new pet alive.)