I'm not an expert, but my advice would be to be more direct & let HER know what you want, rather than YOU waiting for HER to provide you with an indication that you should go all out and game her! Let her know (without being pushy, aggressive or an arsehole) that you're a MAN who knows what he WANTS, and you're not afraid to go for it!
Next time you see her, on a smoking break or whatever, just say something like:
"Hey, the more we chat, I'm actually starting to think you might be pretty cool! You intrigue me, and I think we could have some fun hanging out AWAY from your work environment! I'd like to know more about the girl hiding behind those delicious Mochas you make!"
Obviously, delivery would be key here! I'm not sure what your usual gaming "style" is, but if you say this in a confident, MILDLY cocky-funny way, and without being arrogant, I think you could see results!
Then get her number. Don't ASK her for it! You're a man and you EXPECT it! Just hand her your phone, she'll type in her digits, and you should be golden!
(Any other guys on here feel free to critique this advice. As I said, I'm not an expert, but given the situation you've described, I think this could work!)