Han Sen rummaged around the building. Mister White hadn't told him exactly where the information he needed was, so he presumed it would be easy to find. If it wasn't, Mister White should have told him—that was the logic.
But Han Sen searched the entire building from top to bottom and found nothing. The only place he hadn't checked was Bai Yi's computer.
Gaining access to the computer would require the password. Cracking the password wasn't difficult for someone like Han Sen, though.
In that era, there were many people who could change their physical forms. Thus, using a body-identifier wasn't considered to be a very secure method. Computers were mostly protected by passwords.
Han Sen used his Purple-Eye Butterfly to rewind and get his hands on the password that had been established for the device. After typing it in, he was able to log in with ease.