a man in a room with no doors or windows the ceiling floor and walls are all 10 ft thick reinforced concrete all he has in the room is a table a saw and a tube of glue how does he get out . How he got in there is irrelevant to the question
The original riddle doesn't have a saw in the room. So first, the man bangs his arm on the table until it is sore (saw) then cuts the table in half with the saw.