Sleeping! It was almost midnight. I believe that around ten p.m. (at least that is what I remember) the stewards put out the lights in the steerage public rooms. As far as second class goes, I don't know, but in First class, there was still a good number of men in the first class smoking room, and of course much of the crew was on duty, but otherwise, most were asleep.
My guess would be, that some were sleeping, some were probably in the smoking room. It was around 11:40 or so when she hit, so I say mostly the people were sleeping or were just in their cabins relaxing.
"The temperature on deck felt somewhere around the zero of Canada, although actually, it wasn’t much below freezing, and I quickly rolled into my blankets. There I lay, turning over my past sins and future punishments, waiting until I could thaw and get to sleep."
"I was just about ready for the land of nod, when I felt a sudden vibrating jar run through the ship. Up to this moment she had been steaming with such a pronounced lack of vibration that this sudden break in the steady running was all the more noticeable. Not that it was by any means a violent concussion, but just a distinct and unpleasant break in the monotony of her motion."