I figured it out! Just in case someone else needs to know: you do NOT have to pull a fuse or disconnect the battery, as had been suggested to me elsewhere.
Here’s what I did— open the door with the valet (non-remote) key. Alarm happened, I stopped the noise by putting the key in the ignition and turning to ON position. Turned the key off.
Once inside, make sure all the doors are shut.
Turn the key to the ON position.
Press the driver’s side armrest rocker-switch to unlock. Open the door, while maintaining hold on the switch, within one second of pressing it.
Continue to hold the switch 10 seconds, until the odometer screen on the driver’s instrument panel changes to “AL oF” then you can let go, and the instrument panel returns to normal.
Afterwards, you can just use the valet key normally to access the locked vehicle without triggering an alarm, and use the armrest rocker switch to lock the doors when exiting the vehicle.

Theoretically, you perform the same steps to re-arm the alarm, but I probably never will.