Harry will go to the bathroom right before heading to the altar and ... transfer to Mirror Mirror land, leaving Lara at the altar and Mab seething.
This is my theory, more or less.
Maybe not a bathroom, maybe just the changing-area where Harry takes off his jeans/T/duster uniform & puts on a tux (but it still has the necessary mirror for checking fit&c...)
I don't know, I can see it go either way, the thing is I don't think Lara wants to get married anymore than Harry, between the two of them, they may be able to outsmart Mab.
Agreed: neither of them really want to marry. The thing is, I don't think Mab wants that, either! I think she has a big ol' pile of other agendas based on her telling them to get married... including forcing them to work together to (try to) outsmart her. Mab being Mab, I'm sure she has contingency plans for if they
do get married, but I think her preferred option is for them not to.
The main questions I have are: is it a full swap, with Mirror!Harry coming to Harry!Prime's world (where he's expected to go through with the marriage to Lara)? Because that's part of the OG Mirror,Mirror ST:TOS episode, with evil!Kirk&co coming to the Federation, and Jim has been frank that he's stealing shamelessly there. And then (also based on the ST episode): is it just the Harrys who swap, or is it Harry plus a big pack of his Scooby Gang (and if so,
who?) swapping with Mirror!Harry and
his Posse?
I can just imagine the moment when Harry is standing there at the altar -- seeing
Mab(??!?) in the front row of the audience -- and waiting to see who his bride is... aaaand it's Lara Raith, making Mirror!Harry go "o
shit, I thought I was going to a
safer universe!"
Meanwhile, Mab is thinking, "what the fuck have you done, Dresden,
where is Winter's Knightmantle??!?" And when the officiant gets to "Speak now, or forever hold your peace," it's
Mab who speaks up.