The date on there for the time that the man was taken ill is given as 25th September, and it seems he was taken ill while still at the rave. I think it's doubtful that the same thing might have happened to Corrie, but it might be worth checking that area just to make sure, just in case Corrie was up and walking around on the 24th, after the last CCTV sighting, and did have communication and interaction with people on that day and ended up going to a rave in the evening, then never seen again, and it's just that no one has come forward. The problem with that scenario is that Corrie would probably have been seen by people during the day and that at least one person at the rave, not knowing what happened, might come forward to say they saw him there?
What would concern me would be that if it was a bad batch of drugs then they might not only be passed out at the rave but also in the community. So it could have been sold in clubs the night before the rave. As it was only one person taken ill, I would think it was probably more of an individual reaction rather than a bad batch? Also, Corrie's actions of getting drunk, eating a large meal and then falling asleep in the doorway, don't suggest that he was taking any kind of 'upper' drug like E, cocaine, or methamphetamine, at least not in the club prior to the last CCTV sighting.
I agree that it's a very good find, and definitely the sort of thing to help pad out information of what else was happening around BSE that weekend, because we don't know if there might be something like this that has a connection to Corrie's disappearance.