So I'm in college and I work for the Campus Escort Service. No not a regular escort service

Its for the people who don't feel safe walking across campus, so they call us and we go and pick them up and drive them safely to their destination.
I've been using this job as a way for me to practice openers and just being more social in general. I've been getting some decent results. I had one girl (HB8) that got into the car twice and actually remembered me, and then I proceded to get a few IOIs from her during the ride.
Anway, I was wondering if there was an easy way for me to get a number close. Someone gave me the idea of doing the cube routine, and then making sure my questions ended by the time I got to their destination then I could say. "Well this is your stop, so I can't give you the results now, but if you give me your number I could call you later and let you know." Thus, she would be wondering what the answers meant for a while until I called her.
I don't know if I could really get a number close in such a short amount of time. I live on a small campus, so at best its a 6 minute drive? And I don't really remember if a person gets in multiple times. I would love to get the HB8's number, but I haven't seen her recently. Any ideas? Should I just keep using my job for practice?