This is an offshoot from an old rules debate in DH1, seen in this thread
http://community.fantasyflightgames.com/index.php?/topic/33605-fleeing-from-combat-free-hits/
As of now, movement in DH2 is handled by two actions: move and charge. Both of these actions contain a note at the end where the acting character has a choice of being locked in melee with a character they end their movement adjacent to. Simple enough.
Much of this is actually from the previous system.
Still, it is worth noting the following few things:
-There is no longer a discreet "Run" action. Its been absorbed into the Sprint talent
-In previous systems (or at least DW forward), the "Run" action did not contain the wording that a character can engage in melee if adjacent.
-This prevented the ability to use the Run action as a means of locking key enemies in melee (running up and locking in melee heavy weapons teams, or running up to a foe to be able to free strike them if they don't disengage).
As of now, a character can spend 3-4 AP to move up to a target, lock them in melee, and threaten them with Disruptive Blows if the now locked character attempts anything beyond disengagement, fighting in melee, or the use of rather specialized talents.
Is this intentional, or an unintentional result of copy/pasting the core mechanincs of "Move" without consideration of "Run"?
Should PCs who find themselves in a killzone simply be able to resolve the situation by running directly adjacent to their attackers?