[Robsducati]

This ones got me stumped!
The alarm went off on the Boxster at dark o'clock in the morning, also the rear spoiler was up and clicking, I went to unlock the car on the key to no avail, so opened the door with the key and placed the key in the ignition to stop the alarm.
Shut the door, and went back to bed, then the alarm went off again, did the same thing again, but this time I tried to pop the bonnet to get to the battery to disconnect it, only the bonnet switch did not operate and it looks like the battery is dead....not enough to stop the alarm from sounding though.
The only thing that stopped the alarm from coming back on was to leave the door open, it is in a garage so worth risk.
My question is how do you release the bonnet to get to the battery manually, and why would the alarm and the rear spoiler activate without being tampered with?
The garage was locked.
Any advice welcome.