Yikes c'est pas mal plate ca. My first appartment had roaches. It was an experience. At the time we used the roach chalk. you just draw a line around the walls and doors of your room, if roach walks accross it, ... bye bye baby. Of course if you have pets I think it's bad for them. I presume in a dorm you don't have pets. Alors si tu es en dortoir, viens-tu de l'exterieur de la ville?

Fumigation helps, but I'm sorry to be realistic, they will return eventually, especially in a big building like that, but not likely for some time. I used to live next to a bar. They would spend their days there feasting, and come over when the bar was busy at night.