"Well...It does sound good if we could pull it off, but unless we get lucky on the Repulsion wards, which is unlikely, there's only really the one way out, through the front gate. We'd have to go out that way ourselves, and since they'd be locked in, they'd have nothing better to do than ambush us and force us to let them out."
"If you can find a way for us to sneak past them all, my wonderful and smart sister, we could easily pursue this excellent plan."