Attempt to ambush an opponent
Represents trying to maneuver around to the unprotected side of a
character for a more successful attack. While the normal attack
command attempts to simply barrel past someone's guards, flank
attempts to evade them and strike the person being guarded before
they can respond. If the 'only' switch is used, you will back off
and refrain from attacking guards if you're spotted. Otherwise,
you will attack the guard who stops you by default.