Read before you stay! There are a lot of negatives to this place: it's an older building, the stairwell is extremely dirty, internet is spotty at best, it's in a less-desirable part of town (you might not feel safe walking around the neighborhood, even during the day), you'll be sleeping on a blow-up mattress, the kitchen is poorly set up for cooking, previous guests have leftover food in the fridge that never gets removed, and you'll be sharing a bathroom and kitchen with (possibly) two other rooms.
A few positives: I felt safe inside the unit, given its multiple locks. My room seemed very clean, and Marie provided a second set of sheets. It's a short 15-20 minute walk to the T, and the walk there and back seemed safe enough (given you're in Dorchester).
Overall: I wouldn't recommend staying here. Pay a little more to stay somewhere else, and avoid the headaches / worry.