The Vanished Tenth Customer 2

The woman lowered her head and slowly walked to the refrigerated display case in the farthest corner of the store. She picked out a drink and then headed to the counter to pay. Without much thought, A-Jie scanned the barcode as usual, took the money, and gave the change. The woman's hand was ice-cold. After taking the change, she turned and walked out of the store. Once the woman was gone, A-Jie prepared to tally the accounts for the past hour. When he pulled up the shift records on the cash register, the counting system displayed: "Current Customers: 9". A-Jie froze for a moment because he was certain that including the woman in the raincoat just now, he had served a total of 10 customers tonight. Thinking the system was malfunctioning, he replayed the footage from the store's surveillance cameras. The video showed the automatic door opening by itself at three in the morning, and A-Jie greeting the air, scanning barcodes at the air, and even handing change to the air... It was then that A-Jie noticed something amiss in the surveillance footage: although the counter was empty, the sensor-activated hand sanitizer dispenser in front of the register suddenly dispensed soap right where the woman had been standing...