Example:
Ross Jeffries used an example in one of his vids in which he was walking down a flight of stairs while a HB was walking up. All he said was "Style to burn..." as he passed her and apparently she stopped turned around and asked him what he said. He repeated himself and they ended up getting some coffee right then.
This is what I would do:
First of all I would be swaggering down the hallway DHVing. Chin up and shoulders back. Try not to eyeball fuck her the entire way down the hallway, but try to initiate eye contact 1-2 seconds before your opener.
Smirk at the same time you initiate eye contact and hold throughout your opener.
Whatever your opener is, when you use it, dont stop walking dead in place...As I am opening, i would severely slow down as to almost stop walking, but not entirely. Also, keep your body pointed the direction that you are walking. Only turn your head as she closes distance. This will not trigger the fight or flight response as much because it will seem as though you have better things to do and it's ok if she doesn't stop and talk (little bit of DHV here as well). You have a very limited amount of time to grab her attention so I would do my best to find openers that hit an emotional note with her. Try to make it something she probably hasn't heard before. Try some cold-reads based on what they're wearing, how they're walking, how they're voice sounds, etc. If you're right or the read is intriguing, it'll catch them off guard and will be forced to stop and talk.
If it grabs her attention and she stops walking, stop as well and turn around for the follow up (obviously
) Because you have a very limited time to gain attention, be ready with a quick follow up with your opener. If you open with a neg, have an IOI in your pocket. If you open with an IOI (maybe a genuine complement) have a quick neg in your pocket. Always keep the calibration!
Going off of what PlayHer_Man said, not all girls will want to stop. Some people are busy during the day and really can't. Just get better with your openers and you should see more of them stopping and talking.
Good luck!