Topic got a little off from OP's questions... lol
but my flight was @ 545PM, if yours is 530PM, I'm assuming you're riding Jetblue.
Anyway, if you take the 28X bus right after the interview session is over which is at 3PM, you will still get to the airport on time. If you feel that you're short on time, then you may take a cab but that's like ~$50 where as 28X is $3.25.
To OP,
I was there on 11/29 also. Good luck to you! You cannot trust all the info that people put on predents.com but I see some people interviewed on early December and got accepted around mid December. So I don't think they wait to see how many people make a deposit between 12/1 ~ 1/1 and give out the next round of acceptances sort of thing. I hope to hear them by mid December.
Also, I think you're right about PITT having organized ~5 interviews with massive people with one given day. It seems like every other Tuesday since September 20th were the interview dates, 9/20, 10/11, 10/25, 11/15, 11/29 and 12/13. As you have seen on 29th, I'm sure other interviews also had like ~50 people getting interviewed. That sounds about right because Dr. Etzel told us that PITT interviews ~300 people a year, that those 6 interviews days will make up for around 300 people. For your interest, I remember seeing doc toothache's excel file on acceptance rate that PITT interviewed 330 people and accepted 181 people or something like that.
Good luck to you!