Every time I ride in a Viewliner sleeper, I get a laugh at how 'they' tried reinventing the wheel, in this case, the door latch. On both sides of the sliding door, one put a couple fingers into the latch area and pushed a vertical bar maybe 1/2" sideways to unlock & open the door. Internally, it would lift a small flat rod with a notch in it that engaged a horizontal bar in the door jamb. On the room side, there was a slide thing that would 'lock' the door by preventing the rod with a notch from moving upward. The problem was that try as one may, in many situations, locked or not, the door would simply roll open as the flat rod with a notch would disengage itself probably due to vibration. I, for one, had it 'open itself' while I was seated on the toilet.
Fortunately, within maybe 3 years or so, they removed the 'guts' of those latches and installed the tried and true (for the last 80-90 years, I suspect) 'standard' latch with a substantial post, a heavy notched rod that comes over it, and a heavy swivel piece that prevented the rod from being raised. The old latch bar and finger area are still evident on both sides of the doors.
Perhaps the only downside of the 'standard' latch is that it can't be opened from outside the room whereas the original Viewliner latches could with a key, as I recall. Another downside of the 'standard' latch is the door won't stay closed by itself while away from the room, in the diner or lounge car, for example. I travel with a number of pieces of ordinary carpenters 'shim stock' and jam a piece or two between the door and the hallway side panel at the top of the door when I leave the room. It keeps the door closed and at the top, is usually not noticed by anyone in the hallway. And if I forget it's there upon return and use a little muscle to open the door, the shims drop inside the wall and I'm out 20 cents.
As for entering a room in an emergency, I read somewhere at least 5 years ago that the usual method was to press/push out the hallway 'window' in a Viewliner (not the one in the door) as it can be easily reinstalled by shop forces, supposedly. In Superliners, maybe a crowbar is the obvious quick solution, but damaging the door to open it makes the room unusable until the car is shopped and the door repaired or replaced. I think I'd go for trying to press out the window or smashing it if in a hurry. But then flying glass may injure anyone in the room.