In Dungeon World, Clerics have a starting move called Turn Undead:
When you hold your holy symbol aloft and call on your deity for protection, roll+Wis. ✴On a 7+, so long as you continue to pray and brandish your holy symbol, no undead may come within reach of you. ✴On a 10+, you also momentarily daze intelligent undead and cause mindless undead to flee. Aggression breaks the effects and they are able to act as normal. Intelligent undead may still find ways to harry you from afar. They’re clever like that.
Unlike in some (all?) editions of D&D, Dungeon World does not specify a behavior for undead other than being unable to "come within reach of you", unless you roll a 10+ and they are mindless. The trouble happens when a Cleric rolls a 7-9 and then moves toward the undead.
Now, the undead aren't specifically coming within reach of you in this case so does it leave the Cleric vulnerable to the undead's melee attacks? Are they instead pushed out of the circle of protection via some telekinetic force? Note that the 7+ makes no mention of aggression breaking the effects and walking is likely not an aggressive action anyway.
So, what happens when a Cleric moves toward "turned" undead?