Use the "Restore previous mobile network mode" checkmark in the action and this will return to the previous used setting (like dual mode) that was active before entering the configured cell ID.

I got mine to go only 2G when I'm at my home's wifi, since 3G reception is bllsht here. Once i get out of my house the WiFi will disconnect and i will return to the previous used dual mode. It's simple...

Another tip: I use my MIFARE bus card as a NFC tag to toggle the conditions for a bus ride, so i got it to turn the bluetooth on for my headphones and push the volume up so i can hear it ringing