What happens at Vamsee Mohan High School when a parent is late for pickup?

We are considering Vamsee Mohan High School in LB Nagar for class 6 next year. The main reason is that it is close to home. I do the pickup most days, but I work in a hospital, and some days I am thirty or forty minutes late with no warning. I'd rather hear from current parents than guess. Do children wait in a supervised area, with a teacher, or at the gate? Is there a point after which the school phones the parents? I will ask the office as well, but in my experience the answer at the office and the reality at dismissal time are not always the same thing.