I was touring either a huge apartment complex or office campus. It was several connected buildings and it had a centrally-located food service. The place was so large that the lunch crowd had to be brought through in waves. People were moved through tubular corridors, that had butterfly-valve like doors at each end, in groups the way that mass-produced food products were separated, counted and shuffled to awaiting packages - imagine the way tons of M&Ms are diverted to one-pound bags in queue. Once one group had make sufficient progress through the food lines, a set of doors would open and more would be admitted.
Since my tour was moving the opposite direction as the masses, my presence upset the counts of people in these groups, and the mechanism controlling the flow tried to isolate me by routing me into progressively smaller chambers until I was in a roughly 3-foot square cube unable to even reach my cell phone in my pocket. It gave me a sense of how claustrophobics feel when confined.
Woke up out of breath.