Off the top of my head i would suggest using his environment. If they attack him inside the Inn, perhaps he has secret doors and hallways he can use. In 'Man-eaters of Zamboula', the inn was covered in thick rugs which that innkeeper used to sneak around at night, locking people inside their rooms.

I like giving special characters one or two cool abilities. Maybe Aramis can use an assassination attack. Surely he has body guards, perhaps even some anthropophagi hidden in some basement like compartment he can unleash at the worst possible time (or best depending on your perspective)

Haven't read his stats or anything in a while so maybe some of this is mentioned in the book.

Good luck on the fight! I've yet to get a game going in Xambaala.