Dread if this is such a risk, then may I suggest that you ready yourself for an eventual out-ing. People may notice if you are leaving at a regular schedule, or if you start showing up with new stuff all the time, even more expensive food! If where you live you are surrounded by people in the same situation how do you think they'll react to someone trying to better their situation? Take the job, be as discreet as possible but prepare. Use your current situation of low rent to your benefit but don't abuse it, as soon as your head remains above water I suggest you move on.