I actually found that taking levels in Eagle Eye and staying Cowardly the whole time helped slightly. It got my best character (ironically named Corpse) all the way to level 12 or 13, including Hell's Arena, the Chained Court, and the Wall, while all of my other guys seem to die in level 2 or the Arena of Hell.
He definatley took his hits, but a level or two of Ironman and Hard as Nails allowed him to keep going, and Eagle Eye insured he was hitting consitently as well.
Of course, Corpse was also a lucky bastard when it came to the medkits on the first level - he managed to charge in and grab all four, while all I seem to be able to grab recently are the two sitting outside. I open the door and some stupid zombie has picked up the other two.