Why does this girl keep getting my attention and then running away? Am I seeing things that are not there? How to I approach her?

We work together. She keeps doing things to get my attention but every time she does so, she seems to rush off.

For example she makes eye contact with me, smiles at me and then goes off and chats with her friends.

She "coincidentally" bumps into me when I wasn't looking, apologises and then rushes off.

She'll come up from behind me, say good morning and then walk past me really fast. 

If I say hi to her and ask her how she's doing she'll quickly reply, give me a HUGE smile and then walk off really fast.

Whenever I'm in the area she works in, I get her full attention but she acts like she doesn't want to talk. At most she'll wave at me from the other side of the room.

When she goes past my working space, she looks for me but she never lets me know it.

Now she is a friendly girl. She greets a lot of people and gives them the smile too. I have considered the fact that she's not really that interested and she's just being friendly. But every time I think that, she does something specifically to me that just grabs my attention completely and then runs off after doing it, not giving me a chance to take her up on the opportunity. She doesn't seem to give as much attention to anyone else as she does to me. And when we make eye contact I can feel a bit of sparks flying if that makes sense.

Whenever I feel that, it's usually mutual attraction.

But ultimately despite all of the signs there, I just feel like the girl is completely unapproachable. I haven't talked to her because of it.