If he'd done a little bit of research, he'd have found that the RAF are flying in and out of UAE all the time and there are close ties between the military of the two countries. Sandhurst's also popular with the middle east despots. So plenty of potential sources for research without putting himself at risk.
I would hope that a PhD student would also be savvy enough to know that " researching the impact of the Arab Spring on the country's foreign policy and security strategy" would draw more than a little attention to his activities.
Chances are he'll be released in exchange for a discount on some of the killing kit these countries are so keen on accumulating.