Wow that stinks he took off like that, it does leave you filled with dread. The guy I know was a sort of friend, far from an ideal friend tho. We had a lot of common interests, the main one being music as we are both musicians.
I know it's just a matter of time before I look around and there he is...how I will react will depend on what he does. If he ignores me then I keep walking, if he says hi then I will say hi and then I keep walking.