Should I ask her out or let things be?

Honestly I don't really have the time for a relationship but I'd love to have one. There is this girl at work who I've become friendly with but she has a long time best friend that she's more interested in. However she's been really opening up to me and even catching herself (after the fact) when she reveals some really personal information to me. Hell, I know things this best friend doesn't even know. (I have a knack for getting info out of people just by body language) Now I'd love to start a relationship with her but at the same time I don't want to risk it since she is so well connected with her best friend and I work a dangerous second job. (not to mention plans for the military soon) I just feel selfish if I made a move things turned out decently and midway through I end up getting hurt or worse. I just don't want her to worry about me or carry that burden.