Her whole family was saved by Asher and crew at one point
She just finished nursing school a year early at 20 and became Phillips (the doctor) only real friend. She's basically a daughter to him and his only reason left to live.
Asher called in a favor for saving her family that she would work only for him and help Phillip to keep them all alive and healthy. (Aka stitch them up after getting shot or injured in any capacity)
Not only is Violet getting paid more for her position now, but her favorite part of her job was getting to know the people that she helps. Because Phillip and her were moved to one of Ashers houses she gets to be friends and hang out with the people she works on.
She's super sweet and basically just has the persona of a ball of sunshine. She's incredibly loyal and beknownst only to a few, was put through rigorous training when she was younger which included things such as self defense, torture resistance, verbal evasion, physical evasion, weapons training, etc.
This becomes useful later.