She was trotting at one point but that doesn't mean there isn't a gait hidden in there.
While I am all for someone riding a 4-wheeler around a horse to desensitize them, I am opposed to it when the horse is new and you were trying to make a video to establish what gait she might have hidden under those hooves
She wasn't at all focused on what she was doing, thanks to the 4-wheeler, and it was not her fault.
If you can, try to get another video and tell Mr. 4-wheeler to MYOB for awhile.
Let her stay on the rail the entire time (meaning no short cuts half way across). You don't have to video all that at a flat walk but let her get into and be comfortable walking the rail all the way around.
The rider should encourage her to walk faster and faster (like a human power walking) and see how far the horse can be pushed before she breaks into a trot. Some horses are naturally very speedy walkers and she just may be one of them; on the other hand there may be another gear waiting to be brought out, which is the reason for pushing her a little bit but not enough to frustrate her.
Don't pan the camera, rather keep it squarely on the horse at all times, making sure to get the feet, even if the rider's head gets cut out - sorry to the rider
Be sure to video her as she coming toward you and also from behind. Sometimes little movements in the head or butt might give a clue