I've discovered a way to find an empty toilet cubicle in Abu Dhabi airport (this airport is notorious for the lack of toilet facilities). I don't mind sharing this with fellow travellers since I don't plan to use the airport again if I can avoid it. The answer is this: from whichever terminal you are in, if you make your way to Terminal 1 you will find that there are toilet facilities at the end of the corridors leading to the gates from the rotunda. The toilets are outside the entrance to the gate itself. Now if there is no plane due for the particular gates concerned, the entrance to these corridors are cordoned off by staff. This is course is part of the problem with the shortage of toilets at the airport - they are near the gates and cordoned off. However there is usually a gap that you can slip past and staff don't try to stop you. That way I found a toilet with two empty cubicles, which I regard as a considerable success.