Hope I just can't imagine the terror you must have of going into work. I once worked at a place that was infested with mice, and I thought that was scary. When I protested I was given a cardboard box to put my feet on (I can laugh now, but I didn't think that was funny at the time). One of the men who worked there made an anonymous telephone phone to the pest control who forced their way in and closed the place down for two days while they got rid of them. Rats are extremely dangerous, their bites cause infection and their fleas cause worse. If I were you I would be looking for another job, your health is at risk. Of course pet rats are a different thing entirely, they are clean, well cared for and friendly, but wild rats are a big danger to the community. You shouldn't have to work with them.