As a long time Black Templar player, I thought I would chime in on Righteous Zeal. I think many people get confused on this rule, and GW has not done a good job in offering clarification. The rule states if the Morale test is passed, the unit "must move towards" the closest enemy unit. It goes on to say that the movement is "exactly" like a consolidation move due to a Massacre.
Now, this is where is gets tricky. The statement "must move towards" in entirely different than saying "must move"; the statement in the rule speaks about direction, not distance. The BT Chaplain rule Unmatched Zeal allows the Chaplain (and any squad he's attached to) automatically pass RZ roles and move towards any unit, not just the closest.
To determine distance, we need to refer to the Massacre move in the rulebook. That run states the unit "may" move up to D6 inches. It's very clear that a Massacre movement allows the decision to travel the full D6 inches, part of the distance or not move at all. A Massacre move is not compulsory, and neither is Righteous Zeal (but taking the test is compulsory, unless you have a Chaplain.)
I hope the helps
