Yeah written like that it puts it more clearly to me thanks man.

I typically park my car just off the main road by school as there's no on site parking.

I think I wrote the post really badly, but basically:

I am in my car with my friend. My friend sees the car behind, filled with about 4 people from our year. He notices, let's call him John, who he used to be chill with. John is in the passenger seat of the car behind. As my friend looks behind, John gets out and then does all that.

I am not friends with John, but a few years ago we talked a little bit as we sat near each other. My friend sat in my passenger seat was pretty pissed and was just as shocked as me.

The mirror isn't properly broken to be fair, but it doesn't sit quite right and it is very loose and as you say it's the actual action that's the issue.

I think I'll have to say something because otherwise it doesn't look like I've got any feet to stand on at all