He leaves the room when I walk in?

Why does he do that

Sometimes he seems embarassed around me, and also he used to blush and avoid looking me in the eye and my presence too. When I am beside him he always looks at the cell trying not to see me. It's weird cause when we are near friends he is friendly and smile at me, but when we're in a place he works and i have a course he's not that open. I really am not sure if he's shy, because he used to engage with other people and advertise his culture (he's foreigner) so well.
He leaves the room when I walk in?
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