I have seen a few of the buses broken down in the past couple years. You will be doing the OJ run through the airport. Especially if your gate is 1-99 since there is only one tram running at the airport while they install the new tram car. If you miss the flight the airline will put you on the next available flight. Thankfully is it not next weekend when all Sunday flights will be full and you might have to wait till Monday to get out.