第二个用过去完成时是没有疑问的,第一个在一般情况下用一般过去时,但这里是和
when the plane suddenly turned round and flew back to the airport. While we were waiting to land, a flight attendant told us to keep calm and to get off the plane quietly as soon as it had touched down.里面的动作相比,turned round and flew back, told us to keep calm and to get off the plane
被告知是发生在这些动作前。