I don't now if you can do this or not, but wouldn't it be cool if you could take someone's eye and use it to open doors that the owner of said eye has acess to. You should definately be able to.
Yes, I think you should be able to use people's hands or eyes to open doors, either by taking it off or preferably even by dragging their sleeping/unconscious/dead body to said door and scanning them without their knowledge.
It's be neat if way down the road, you could use that to steal money from their bank accounts too.
Ooooh, that'd be a whole new kind of thievery!