I suspect those were people who were not wearing their seat-belts during cruise...
Here we go again. How that makes my blood boil. CAT can be very unexpected as we all know. Was the seatbelt sign on? If not, the cabin crew would have been going about their business in the cabin or galley and with an B777 full of pax there will always be a number on their way to or from the lavatories. If (in the cruise) the operator has a self service refreshment policy operating from the galley there will also be a small number on their way to or from the galley. Sure there are those that stay unbelted whatever, but on a ten hour plus flight (when the seatbelt sign is OFF) there will always be some movement in the cabin for valid reasons. These are most likely to be the ones that get injured in the event of UNEXPECTED CAT.