Looking at the next bit of CCTV (when he walks to the bin), there's no obvious sign of a mess on his clothes as far as I can see. So if anything 'distressing' was seen on the doorway CCTV (vomit ... the other end ... etc.), it wasn't anything that left an obvious stain!
I think Nicola's quoted comment of it just being 'not the best view of him' sounds quite reasonable. I know we'd all like to see it out of curiosity and to see if it gives us any more clues, but I expect the police would only release it if it would benefit their investigation to do so.