I don't know if they take walk ins, but Long Beach was quiet enough that (if they do) it could be worth a shot.

I got there early, fearing it would be a DMV-like madhouse where appointment times were routinely ignored. I instead found a quiet office with just one other applicant in the waiting area.

They interviewed me an hour before my scheduled time and I got a quick approval.

Of course, it may be chaotic at other times. I'm just one data point.