Hallucination
This happened yesterday evening. I was in the shower. The rest of my family members were out; My father went to buy us bubble tea (under the pestering of my sister), while my sister and my mother went to buy dinner. Like I mentioned just now, I was bathing.
Some time into my shower, I started to hear the phone ring. It was most probably my father. However, that does not explain what happens next. The phone kept ringing, stopping for a moment, then continuing again. This repeated several times. My father would have known to stop calling after once or twice if no one picks up the phone. But the phone rang several times.
Then, I thought I heard voices from outside the entrance to my house. I recognised the voices to be of my sister's and my mother's. I knew my mother would have brought her keys, so I continued showering. But the voices seemed to remain outside the door. A little puzzled, I continued showering. Then, I thought I heard my sister calling for me to open the door. I wasn't really sure if that was what she said, the sounds muffled by the shower, but after this continued for awhile, I quickly dried and clothed myself before rushing out of the bathroom.
No one was outside the house. Or in the house, for that matter.
To make sure, I even looked out of the window to make sure no one was outside. No one was outside, not even a neighbour passing by or the stray cat that my sister likes to play with. Puzzled, I went back to the bathroom to continue showering.
My family soon came back after that.
PS. If you were wondering how all this happened while I was showering, the average time I spend in the bathroom for my bath is half an hour. :D