So you're looking for your friend. But you don't know which unit she lives in. That's ok. Why not use the process of elimination and start walking into random units yelling for her? Knocking is a good idea and I'll give you that much credit you tried that. But when I didn't answer the door immediately, you opened the door and strolled on in yelling her name. I suppose if you want to take a broad view of the thing, it's my fault for not locking my door during broad daylight. Now that I know a crazed psycho stalker with the IQ of a raisin is prowling around the property, I will. Don't try that again. All you will find here is an old fashioned cast iron frying pan upside your head. And a generous kick to the balls when your sorry ass hits the floor. —Not Your Friend