It occurs to me that purely by RAW, one cannot "Ready" a "Disengage" action, because even if the Trigger occurs, and you use your Reaction to take the Disengage action, you can't actually move, because it is not your turn.
Now,
I would be inclined to ignore all that, if I were DM, but I can't say that I'm sure that I'd be 100% consistent about that ruling. Naturally, I bow to
@TaranTheWanderer in this case, and I will change my post if necessary.
Let's discuss:
1. Given it's a pbp, and there's no initiative, you could just wait until Lidgar posts deidre's turn or announce that you 'delay' (is there a delay action??). But, once again, you could just wait to post. It's helpful to announce these kinds of things, though, as it lets other people know what you're doing.
2. This part of the adventure is pretty loosy-goosy and I'm not really tracking movement(or initiative). It's more narrative (although, it's hard to disconnect the narrative from the mechanics when I, literally, posted a gridded map.)
Summary: don't sweat it.
The important thing I need to know is whether you are retreating and, thus being safe against further attacks or whether you are helping the last of the Mourners pass safely ahead of you and thus risking yourselves to more attacks. Movement is irrelevant. If you choose to retreat, you have enough movement to do so, no matter how far you are from the gates atm with no AoO
As far as RAW goes?
I guess, technically, you'd have to ready a move action. But that won't let you disengage. Can rogues disengage as a bonus action? If so, a rogue could do it.
In 3.5 you could ready a withdrawal.
Honestly, for the amount that this is going to come up, it doesn't bother me. If it becomes some kind of core tactic that the party uses to kite enemies or something, then we will revisit.
On the note of rescuing people:
I hadn't thought of the idea that you could grapple people and pull them in with you. That was a tactic I hadn't thought of which might let you have your cake and eat it too. In which case, I might be a bit more of a stickler with movement since grappling halves your movement and your movement becomes a bit more important, so I feel you may have to count squares and see if it's worth the risk. It also puts you at the risk of Opp attacks. So yeah...my whole spiel of 'not counting squares' isn't exactly true.
@Kobold Stew You can move the old lady if you want. Despite the 5 feet. I counted it and you have enough movement.
