As you exited the bus, you heard the apu running it is a small jet engine in the tail which provides electricity to the airplane and air for the airconditioning...sometimes the boarding agents put the passengers on the bus to get rid of them before the crew are ready to accept boarding...irresponsible yes, uncommon no...no the engines are not running this costs money
...especially if a passenger gets sucked into one..this will delay the flight as the person's bag has to be located and removed...and their remains washed from the engine...we cant have delays can we??
note..I dont work at Qatar Airways, but have ridden on them many times, and never felt them to be unsafe in any respect..in fact the planes were so well groomed and kept you could eat off the lav floor...and the lovely asian cabin crew..mmm yummy...
but it is a pain as a passenger to wait in the bus when the boarding agents just couldn't be bothered to look after us until the crew/aircraft was ready....and this happens at every airport I've ever been to where a remote parking area.(no airbridge/jetway) was available...