I made a knot in my own head with the Broodwalker's Hive Defense rules and I was about to post about it but I found the answer alone.
I still post it in case someone else wonder the same.
Is it me or it is just impossible to attack a master broodwalker with a melee weapon ?
Master broodwalker have the Hive Defense ability : Heroes treat each space adjacent to this monster as a Hazard space.
Hazard space have the same properties as Lava space and thus : "A figure entering a space containing lava immediately suffers one damage. Any figure that ends its turn in a lava space is immediately defeated. Heroes that are defeated in this way place their hero token in the nearest empty space (from where they were defeated) that does not contain lava. A large monster is immediately defeated only if all spaces it occupies are lava spaces."
I had misread the rules and though : "a hero finishing its movement on a Hazard/Lava space is immediately defeated" (it had sense in a role-playing manner).
Thus the broodwalker master was undefeatable by my melee-only heroes !
I was about to ask if a partial consuming of the movement point (movement-attack-end of movement) counted as the end of the movement...
but as I just quoted "[...] Any figure that ends its turn in a lava space is immediately defeated. [...]"
That means you can end movement in Lava/Hazard space, you just have to pray that you have action or movement point to get out before the end of your turn !
Hope it will help some of you,