Girl turns head to look at me when talking to other people?

So at gym girl is talking to another guy on treadmill he is on her left, but when I walk down the line behind the treadmills she turns her head to her right to watch me? Its like she senses me and turns her head to me whenever I enter the area , even if she is talking to someone else. Thoughts?

Girl turns head to look at me when talking to other people?
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