the cell conditions

I think we can assume that the prisoners during the time of the Puritans were treated to the most ascetic conditions possible. While we would not need to think of them as being "tortured," the Puritans would have assumed that people who needed to be imprisoned would need severest punishment. Further, since this play focuses on the horrible sin of consorting with the devil, we can also assume that these prisoners would not be treated particularly well. We can believe that there would be few amenities (no showers, exercise outside) and that the food would be spare at best. For the Puritans the people should be in the cell to "wrestle" with their very souls and thus would have no contact with anyone other than the guard as they try to regain heaven.

It was, as you can imagine, not very nice. Miller describes it as a place with "high barred window" with two benches along the wall". The only light is of the moonlight "seeping through the bars". There was no toilet or even bed. Check out the beginning of Act 4, Miller describes it there.