While I understand the desire to learn about Google from the inside, planning to stay there only 6 months isn't very fair to the employer; the OP may have learned a little from the experience, but Google likely got almost nothing (net) from the employee as it takes more than 6 months to become really productive at Google.

I actually would not want to work with this person knowing he's pulled a "stunt" like this; I think it's unethical.