They watched as someone emerged from the house and, without thinking, Jon fired off the device. As he did, however, Karyn pushed his aim to the side, which caused the house to be "vaporized" instead of the person coming out of it. After the house disappeared, everything else that was within it disappeared as well. Obviously, since there was no building, there wouldn't be any furniture or other belongings either.
And in only a few seconds time, the McMillan house was completely gone, because it had never been built.
