I stayed downtown in a hotel across the street from the large Department of Education building. I watched from the window as I observed about 6 or 7 people enter between 8:30 and 9:00 am - and then headed to my day. I got back to my room about 5 pm and looked out the window - seeing about 6 people walk out over the next 15 minutes, and then nothing more.
I would estimate that the building could accommodate at least 1,000 staff.