where is their global entry office?

check https://ttp.dhs.gov/schedulerui/schedule-interview/location?lang=en&vo=true&returnUrl=ttp-external&service=UP

It is located directly above and behind Delta Air Lines' ticket counter according to U. S. Customs and Border Protection's website. For more information about the location and telephone number of the office, please visit the following website. https://www.cbp.gov/travel/trusted-traveler-programs/global-entry/enrollment-centers/washington

I suggest you visit the website for all this information.

Sorry, I can't answer that one