Ooh, good question.
If Murasa's as tough as I think she is, we might just be able to take one or more of these tengu for our own purposes. That'll give us the bargaining chips I was hoping for back in the corridor, and make our position much stronger.
We should try to save at least the majority of the rope. At best, I think we can hope for two prisoners, one of them's gonna get away, I just know it. We won't need ALL this rope, just enough. Plus, I'm not clear if they took ALL our gear, or just our weapons. If we still have our pack, we have our own rope, as well.
Of course, this is all assuming their pet ghostbuster doesn't waltz up the stairs next post and trap Murasa, but hey. We can hope.