Most denizens of the guardhouse eat their meals here 3 times
a day (though guards who are on duty take their meals at their
posts). The hall stands dark and empty the rest of the time. The
boxed text below assumes that the PCs visit the room
when it is empty.
 

This shadowy room has f4 exits, all doors. 2 are in the south wall, set into alcoves. There are also doors to the north and to the east. The chamber has a low dais at the west end. A sturdy-looking table and comfortable chairs stand atop the dais. The eastern portion of the room has 2 longer tables, each flanked by wooden benches. Rushes, both fresh and dried, cover the chamber’s floor in a thick layer.

The great hall holds nothing remarkable. After each meal, Brubgrok’s
servants gather up the rushes (along with any food scraps)
and burn the lot in area 12, then put new rushes down in the hall.

>>12.