I think it's a good guess that Hashim lured Bristy by taking Zamil's phone + pretending to be Zamil... I wonder what he said. Maybe faked a family or some other kind of emergency? She was a good friend to try to rush and help him.

Poor girl couldn't have known her life was in danger.
I am shocked no one heard anything too... student housing walls are paper thin! I guess if the murders happened around the time Bristy was lured away, 10am on a week day, most would've been at work or school... still crazy though.