Coward mice!

Presentation:
First of all, Hi! I´m Joaquin, from Argentina. I´ve bought recently mouse guard and I´m planning to play it with some friends shortly. So I decided to register in this forum and start posting here all my doubts. My RPG experience is pretty much d&d and warhammer, so I´m not used to these games yet.

One of my players in a future campaign has already started to think about his new character´s concept. He wants to play a sort of coward mouse. At firts I said “Great, that´s gonna be difficult…”, but now I see that writing a good belief and/or instinct, having a high nature, and with the fearful trait, he can perfectly run a coward mouse.

BUT I´ve started to wonder some ways he could “act cowardly” in a conflict, and how could this be runned by the rules:
-The first one is using fearful trait, not much of a problem.
-He told me he´d always hide first when in combat, try not to get exposed. Choosing “defend” would be a good way to do that? And maneuver also looks good, if he wants to backstab next. Both of them use nature, also.
-If he sees he´s going to lose a fight (not a fight to death), and therefore wants to run away (even if his team doesn´t), what should I do then? The book doesn´t explore that possibility, except if one thinks of it as “surrender”.
Also, if it is a fight to death, and he wanted to quit it when he´s going to lose (like running away alone), would you allow him to do so? I personally wouldn´t, as he accepted the risk when entering the conflict, and there shouldn´t be an easy escape way. Maybe telling him he´s got to decide before engaging on it. What would you do here?

Oh, his belief will be something like “A living soldier serves for another war” (it is a saying here, I don´t know if I translated it well). But I´ll open a thread on that´s what we fight for to discuss it.

You as a GM and even other players can force him into a conflict. To play out his character set cowardly goals. Goal: escape.
He can also try to avoid conflicts by persuading people not to fight or turning it into a chase. It should be pretty easy.

I’m sure he can run away instead of helping out if the fight struggles on for another run of three action. Maybe he has that choice even between each action as long as he’s not the one rolling (then he’s the main actor for the moment). Either way, if he decides to hide or run away you might want to force him to take a conflict with only him in the team (and thereby have a fight with two teams with mice) and a goal like ‘‘I want to hide from the owl (or whatever)’’ or the like. It’s not always possible to get away unnoticed only because you don’t help out your friends.

If his opponent wins without compromise then I’d say he’s dead, as you say he accepted the stake when entering the conflict. If the opponent wins and has to accept some form of compromise let the mouse escape and if it’s just a small compromise you can give him conditions like tired and injured or introduce a twist like ''your opponent is at your hells as your fleeing. You has to roll for escaping (or even a new conflict for fleeing).