1.) How far are the lockers/bathrooms from the testing room?
I am guessing this will vary from location to location.
But, typically it will be on the same floor.
I think mos test centers are just a suite in an office building, so expect typical office building settings.
2.)how long did you have to wait for your proctor to sign you out/in?
They'll need to look at your ID and fingerprint you every time you sign in and out.
The whole process takes about... 1 min I guess.
Signing in/out is not a big issue, from my experience.
As far as the snack is concerned... I brought some but ended up not having them because I was too pumped up to think of food.
You won't feel the hunger with the adrenaline rush.