Ringing

I was on the bus this morning, when suddenly it comes to my attention that somebody is not answering their phone. I can hear this ringing going on and on and on for minutes and minutes. Everybody starts looking around quite annoyed. I knew it wasn't mine, because I know my ring and that wasn't my ring (anyway, nobody would call me at 7.30am, I am far too asleep to make any sense of any conversation). As time goes by, people just get used to it, but I still find it so annoying and really look around at who could be the culprit.
Anyway, I then realize it might be an alarm clock incorporated in the phone and find it very funny that somebody doesn't realize their alarm is ringing.

Suddenly it stops with a strange blip sound, that shows that the battery on the mobile has run out..... at that instant I realize it was my phone! I felt so embarrassed, I think nobody noticed that it was me, but a guy looked at me with an annoyed face, so I think he knew.