Emergency Defibrillator

At work we recently put in a emergency defibrillator. Every time I see it I giggle a little inside. The thing is in one of the kitchens but its in this huge case and here is the kicker, it has a red ambulance light on top of it. I picture an alarm going off if you ever open it to help someone. I don't get it, why would you want a red alarm light on there?? Is it important for every nosey assistant to come running when they hear it. If I leave this place I am going to open it to see if the alarm goes off.