I think some RAF heads should roll here. Security was clearly poor, as there is a known protest at this base, so this should have been foreseen. Only a naive person would think that 'baddies' do not get involved in protests anymore. If I were a terrorist I'd be 'glamming up' in my best tree hugger baggy jumper.......
With enough room under it for an AK or some explosives.
Of course, I can't claim to have invented this idea. Some nasty fellows have already done something like this at a weakly secured part of a base, but that cost the USMC rather more than just embarrassment.