In the day, zombies will probably shuffle, it the night, they run, at you, in great numbers!
I'll 'flick' this idea a little ...
I'm not sure about a wheelchair, but if you found a crutch in the hospital, could you use it as a melee weapon against zombies?
As an on and off wheelchair user and more on than off crutch user I wouldnt be opposed to them. I think however that a wheelchair would be a better candidate for mods on an RP server, though crutches could have a good use in the base game depending on how the medical system works, a broken or sprained leg for example could heal somewhat quicker whilst using them and while injured perhaps you could move slightly quicker with rather than without them at the cost of making a little more noise.