Tiny black dot on iPhone 5s screen?

I just dropped my phone. It fell on the screen. The screen isn't cracked and there doesn't appear to be any new scratches. Now there's a tiny black dot on the screen that won't go away.

I broke my friend's phone

It happened last week. Basically me and my friend (we r both 13) were walking to the nearest train station from the cinemas. She was immersed in her phone and I told her to get off it because we were crossing a road. She didn't listen. A car was coming up at her who wasn't paying any attention so I ran and pulled her out of the way of the speeding car, and she dropped her phone when I was pulling her. During that time I had broken my ankle and patches of skin were ripped off. She screamed. Turned out she was screaming at her cracked phone rather than my hurt ankle. Anyway I'm in hospital whilst have stitched up my ankle. She visited me today and said I have to pay full for a brand new iPhone 6s (she had the iPhone 6). I told her that I didn't have to pay for a brand new one as hers was already old. No asking me if I was better, just demands. Her parents said they will sue my family if we refused to pay. I mean, a. I saved her damned life and b. She's demanding for a better phone without asking me if I'm better. What to do

Why was my iPhone making a fire alarm-like sound?

So I'm on my laptop playing League with headphones on while I'm on iFunny in the comment section when the [fire] alarm-like sound started to sound. I looked down at my phone thinking it was a video, but I realized I was in the comment section so the sound couldn't have been coming from my phone. So I turned my phone off. I then look around in an attempt to find the source of the sound. I looked at the fire alarm in my room, but the alarm wasn't there (we needed to get new batteries). Then I looked at my DS and it wasn't coming from there or my laptop. So I grabbed my phone and put it to my ear. The sound was coming from it. I was afraid because my phone was off and it wasn't a notification sound. In fear that it might explode, I put it at a distance from me.
My best explanation for the sound was a fire alarm sound that kept repeating. (No it was not an amber alert noise either).
Why was my phone making that noise? Should I be worried?
Extra Info: I have an iPhone 6 and it was not charging when I was using it.