"Your gran's going to be fine," I repeat as we get to the airport. But I'm soon having second thoughts. Our flight is delayed by an hour-and-a-half and the terminal is hot, crowded and airless. By the time we are boarding Mrs Walsh has started to turn pale. Just before take-off she begins to look clammy. It's the last chance to take her off the flight to get her back to hospital. About 150 passengers will be very angry if I get the plane sent back to the gate now. But if my patient is in trouble it has to be done.