Is that concept drawing missing a step? I expect the two steps outside the space is correct, and there's an omitted step in the theater.
I personally like the idea of a wide entry hallway but I can't say I am a fan of the walk to the av rack. The hallway is a nice opportunity to build a little drama to entering the theater.
I do wonder if one has a nice movie collection, if some media storage might be worked in, if the av rack went to the other end of the hall. Not sure what depth is there, but a side by side rack could
be supported side wall to side wall, on some steel. A lower panel could be removable, for rear rack access, depending on the depth there. That common wall might also work well for an actively
cooled stack, where you could bring in cool air from down low, and vent up top, using the volume of air from the room beside the theater.
I gather there's to be a daisy chained smoke detector in the theater? And I'd look into if there are any codes regarding the doors swinging outwards. The again, that window is a potential
secondary egress. I expect it will be covered over, but if it isn't, you might find with the riser, code might be asking for safety glass.