Early wake-up call

We woke up this morning at 4 am to the sharp sound of the fire alarm. No reason could be found. The alarm was mounted on the ceiling at a height of 4 m and a ladder had to be retrieved from the outdoor storage room to access the alarm. The alarm screamed the whole time, and we couldn't turn it off until we got access to the battery after unscrewing three screws. Such an alarm clock today.