what does "that's always been the master"mean?
Eli paused when his light played over another panel. “Let me think.” And orient himself. “This should come out on the second-floor landing. See how it forks here? That one should come out in my grandmother’s bedroom. That’s always been the master, as far as I know. God, we’d have killed to have these open when we were kids. I could’ve snuck around, jumped out and scared the shit out of my sister.”does this "master"= the master passway? or the master's bedroom?