LYD,
There is a cafe about 50 yards from the Observation Area called 'Cafe Chi'. Its between World Business Centre 1 and 2 (but you can't miss it) and looks as though its only for people in those buildings, but anyone can use it. It also has 'bathrooms' which you can use.
You can get back to the Central Terminal Area by using the same buses, which stop right by the Academy (again free).