Thanks to the kindness of the passengers in front of her and the request of the airport staff, Zhang jumps the queue and reaches the counter in time. She checks in her suitcase, leaves the counter with her boarding pass in five minutes and heads for immigration and security checks.

In a couple of minutes she reaches a sculpture of a Chinese armillary sphere, which is flanked by restaurants and shops. It's a T3 landmark, and this is where international passengers have to be careful.

They have to walk straight ahead to get on a train to reach the international boarding area. Instead of doing that, if they take one of the escalators on either side of the path, they will end up in the domestic boarding area on the third floor.

Zhang takes the right way, walks straight ahead for five minutes till an airport security guard stops her to check her boarding pass.

But why does a passenger have to go through all this to reach the boarding area? The airport officer in charge of passenger service, Tang Hua, says the checking posts at the entrances of international and domestic boarding areas will prevent passengers from going the wrong way. Once that happens, a person can easily get confused and lost - after all T3 has 175 escalators, 173 lifts and 437 travelators.

After the security guard checks Zhang's boarding pass, she is allowed into the international departure area. There are three escalators in front carrying passengers down to the second floor, where people have queued up to get on the Automatic People Mover (APM). It is one of the two transit systems in the terminal that links the check-in area with the international boarding area. In case it breaks down, passengers can be carried on shuttle buses from outside the building.

Zhang has to wait for about three minutes before getting on a small train of two carriages. The train speeds down a slope, runs through the T3D section - decorated in dark colors - and then goes uphill before reaching the boarding area. The entire ride takes four minutes and is absolutely smooth, except when the train makes a sharp turn in the last minute near T3E. Some passengers not holding the handrails are thrown off balance - a few even trample on others' feet.

After getting off the train, Zhang goes through the quarantine, immigration, security and Customs checks, and reaches a fountain surrounded by duty-free shops. The whole routine takes no more than 15 minutes.

Since her boarding gate is E29, she has to walk only a few steps. She reaches the gate around 2 pm, well in time. In fact, she has to wait for seven minutes before an airline staff announces it's boarding time.

Zhang says she is lucky to have gone through the entire procedure in such a short time. But she has a word of warning: "If you are actually traveling abroad, you better reach the airport earlier."

The entire procedure she went through on Saturday was a drill, the sixth and last before the terminal is thrown open. And there has to be some difference between real travel and a drill.