I accidentally triggered the security system on my Toyota Sienna. I think I unlocked manually using the switch on the door after locking by clicking the remote, which is a no-no.

Flashing lights and horn, and all the doors kept locking every time the horn went off.

I had to turn the key in the ignition to get out, although I think somebody with faster hands could have flipped the door lock and opened the door before it locked again.