[The answer to Graham's question is perhaps apparent by the ink-forged monkey that lingers nearby. Sai doesn't dismiss it immediately, as there may yet be further use for it, but he does pick up the scroll and pack it back in his bag.]

Any door can be opened easily from inside.

[He says, by way of answer when that's done.]

If we could not get inside without damaging the door, I simply needed to place something else inside to give us access, instead.