OOC:
Ok, did some checking (and maybe put myself on a watch list...hope that doesn't come back to haunt me... XD) You need to kill the phone and the power. There will be a delay, between 30 and 60 seconds. You all have enough training or personal experience that you can probably figure out where how to do that. There are no basements in this town because of the potential flooding. So the breaker is probably in the kitchen which makes up the back of the building. The phone line also seems to run to the back. If the phones and the power were cut, no one would know until morning.
And if we want to retcon this so that you all knew this and moved to the kitchen window after seeing the keypad, that's fine too.