Thank you Kendesign this is exactly the kind of response I was hoping for.
It definitely helps with how one would go about making such an encounter, making the threat of the beast not just about the physical damage it can cause but the emotional trauma it can threaten to create to character relationships and the like. I have not actually had chance myself to play or run a game of Mouse Guard yet and have only recently read the comics so the importance of relationships and how predators can effect that is something I have not yet experienced in terms of actually roleplaying within the Universe of Mouse Guard, but its importance is definitely highlighted in the conversations on this forum.
But in essence your reply answers any questions I would have about how to implement the danger and perhaps subsequent death of such a large threat within the confines of a small Patrol.