He could easily have exfiltrated the data without ever leaving the premises. All he would have to do is is walk into a lab room with an unsecured terminal to up

He could easily have exfiltrated the data without ever leaving the premises. All he would have to do is is walk into a lab room with an unsecured terminal to upload the files, or used his phone to upload the drive, there aren't hundreds of ways to pass the data off once it's on a thumb drive.