The fastest and the best way of finishing this quest is by finding and entering the abandoned house.
Once you're inside the abandoned house, you will find some objects laying around that make specific musical pitches. In order to activate the Fail-Safe terminal, you will have to enter the correct tone sequence, which is: Radio, Pitcher, Gnome, Pitcher, Cinder Block, Gnome, Bottle.
After entering the correct tone squence, the Vault 112 Auxiliary Command Terminal will appear.
Activate the terminal and initiate the "Chinese Invasion" and exit the abandoned house.
After leaving the abandoned house, you will notice some Chinese soldiers killing everyone in the Tranquility Lane, except you. However, you will receive positive Karma for freeing them from eternal suffering.
Exit the Tranquility Lane through the door located in the playground.
After exiting the Tranquility Lounger, you will notice Dad (James') sitting outside.