Another question

Did anyone else wonder why Mrs. Gertz seemed to be so against Mark in the beginning? The look she gave at the party when Ali, Mark, and Mr. Gertz were all conversing seemed questionable. Then in the next scene when Ali says she needs to go to the bus station, is getting a cold, and Mark is picking her up brings it up too. Mrs. Gertz says, "Oh Mark, yes I see." What was that supposed to mean? Did she think he was a bad influence because he was successful? Or did she just feel Ali was running off with him too quickly? Granted, Ali got violently sick and had to come back anyway. But what about when Mark found out Ali had AIDS? He got scared too as a result but did not run away immediately. Shouldn't Mrs. Gertz have considered that? Just my thoughts!