[Momo gives a hum of agreement to that, because he always loathes seeing others hurt, but there's another aspect to this for him as well. Since he'd had such a big hand in bringing leyline cleansing down here, he's going to feel responsible if it flushed out something they can't deal with into the tunnels.]

It makes sense, even if it's a bad situation. Cwyld normally responds strangely to magic or uses it to feed off - it's just usually only if you outright interact with it. It's why you can't use normal healing magic on it and why the Wilders usually recommend not directly fighting a Shade with magic. So if this is some kind of worse strain, interfering with and warping magic is a logical next step.

[Even if they're not directly interacting with it, and it now seems like more of a situation of entering its "territory" setting it off.]