Some Blue Court people turn into bats and get up that way. I saw someone climb up by clawing up the side of the building, once, so it is certainly possible. If inadvisable. Castle walls are not known for their cleanliness, and now they are crammed with roosting pumpkins.

[ He's also doing math in his head, looking between Maria and the window. ]

If you started from higher up, it would honestly be safer. Most of the pumpkins are further down.

[ He's thinking about it. Never tell a joke to this man you're not willing to have him seize upon. He wants those books. ]