When healthy each dupe wants their own mess table.
But when in a hospital they will happily share the same mess table, even sitting down in it while someone else is already using it.
Maybe they only check for occupancy before deciding to sit in it, so when multiple dupes start at the same time, they all see the mess table is unoccupied and use it?
It seems to work fine for the toilet...
Have multiple sick duplicants in the same hospital but only have a single mess table.