We may ask, “should you go to the restroom prior to boarding?” or “should coach passengers be able to use the first class lavatory onboard?”

But we rarely ask, “where’s the lavatory? Oh, is this it?” before opening the aircraft door.

But via @JohnnyJet, that’s what happened on a recent China Southern flight.

A 50-year-old woman didn’t want to wait in the queue for the plane’s lavatory, so she went and found another door figuring that doors lead to toilets. Then “[p]assengers said they heard a hissing sound as the slide deployed.”

The incident occurred while the Airbus A321 was being prepared for take-off at the airport in Chongqing, in south-west China, before a flight to Shenzhen [Friday] afternoon, Shanghaiist reported.

Boarding had just completed when passengers on flight CZ3456 heard a loud hissing noise

The flight was delayed for a couple of hours but the woman who popped the slide wasn’t allowed to continue the journey.

Following the incident the woman’s boarding pass and passport were confiscated by cabin crew. Later, instead of taking off, she was taken away by police for investigation.

Over the past few years, China has been hit by a wave of passengers opening emergency exits for rather trivial reasons. Last month one passenger did it because he wanted some fresh air, and another in 2014 did it because he was in a hurry to disembark.

For the uninitiated, this is a lavatory

For those unfamiliar in such matters, it’s usually ok to use the lavatory when the seat belt sign is on and what’s more important is what it smells like when you’re done.