Um... they've already paired up Xander with Renee.

I'd say their mild flirting doesn't quite qualify as a full-on "pairing" prior to this issue. Of course, we don't yet know exactly what they do directly after the battlement conversation at the start of this - maybe they got down to it first, and Buffy and Satsu walked in on them and got inspired, and then Andrew comes in and fixes the cable, and...