Personal alarm

So I go to my last class of the day and I'm talking to my friend, right? Ya so while we're talking I tug on my purse's chain and 

BEEEEEEEEEEEEEP

Somehow I set off my alarm??? 

I ran out of my classroom clutching it to dull the noise while my teacher was also coming trying to help. We were trying to figure out what the hell set it off so I looked at its description on Amazon. I accidentally spilled some of his coffee onto my shoes thankfully it wasn't hot. We found out I somehow pulled the pin out of the alarm????

This entire time I was running on 2a's adrenaline and anxiety