Runner,
I have no idea why the rush. It sounds like this dentist doesn't have a very full schedule if he can get you in for 5 hours at a time and move appointments up OR he gets a lot of cancellations.
Root scaling or root planing is the debriding of the root surfaces in order promote reattachment of healthy tissue. Usually they will freeze the area if the pockets are really deep (6mm or deeper), use hand scalers or ultrasonic/piezo scalers and sometimes irrigate with an antibacterial solution.