It seems like the 2 girls only observed 1 dead girl From what I understand ?Having been a sorority girl with a lot of roommates, I imagine that everyone slept as late as they could manage. One of the survivors thinks it's weird that she's the first one up, checks on non-survivors, clearly sees that something is horribly wrong (might even go into shock), calls friend not in the house who tells her to call the police/ambulance. This chaos wakes the other survivor, who also looks at situation and has similar reaction, so dispatcher ends up talking to more than one person.