It's the middle of the day, and the teacher's phone suddenly stops working. He's not sure what's going on, but he thinks it's a coincidence that his phone is out of power at the same time that he hears a whistle. He figures that if there'd been a car crash, he'd have heard the sound of the crash. He asks the teacher to wait until the next day to tell him the news. The teacher says that's fine, he just wants to make sure the gap between them doesn't widen. He gives the teacher a ring as a birthday present. The ring isn't a marriage proposal