Most Helpful Girl
Yeah I think that's fine. Ask her through a text message but make sure you're already having a conversation so you can segue into it. This way you can feel her out based on her responses. You can then mention it again in person if you like.
Most Helpful Guy
So... you'd leave a paper trail? No, don't do that. You don't want it photocopied and dispersed in case she goes all high school on your ass, and on top of that, if she decides you're sexually harassing her, she's got some strong evidence against you. Wait for a discrete time and ask verbally.
Do you really want to ask people out at work? :/