What are you reasons for ruling out AWOL, out of interest?
I'm thinking spontaneous AWOL, drink fuelled and following a let down of a night out (friends leaving without him, change of plans from the original party, getting escorted out of the night club). This could have been the "final straw" and led to a need to get away.
I do think there was third party involvement. To fit with my line of thought, I would say he met with someone in the Horseshoe area who handed him a change of clothes, cash etc. I agree with the people saying the figure captured on CCTV could be Corrie.
The third party may have come forward in confidence to the police and told them what happened (hence their lack of visable "effort").
The problem is that Corrie is not where he said he would be and has not been in touch and an other option has to be considered. Did the attention that this impromptu AWOL bring, and the questions being asked of him, lead Corrie to take further action?
I think the crucial info, in this case, is what is not being said about his general wellbeing.
All my opinion and based on my readings on here. Hope I've not broken any rules, have tried to put my thoughts across as discreetly as possible.