But this approach can be used later to lock down suspects, though it's too complex to prove assumptions in the early stages.
So Fang Ze came up with a second idea: to inspect the soles of the crew members' high heels.
The train Fang Ze was on is a magnetic levitation train, and the track retains certain magnetism even when powered off.
And many women's high heels have iron plates on the soles to prevent wear. So... if the train from a couple of days ago was indeed a projection, then when these crew members "boarded the train" for checks over the past two days, they were actually standing on the tracks.
Under the influence of magnetism, the soles of these crew members' high heels could also become magnetized, so it would only require testing with an iron wire.
Thus, Fang Ze went to the crew members and asked them to take off their shoes, using iron wire to test them.
