Something about this doesn't feel right. The time of flight is all wrong for a compressor wash although details should be forthcoming soon if that was the case. Perhaps it was one of those other things that previous contributors have mentioned.
The thing that doesn't feel right though is the fact that so few passengers fell ill because of this smell (6/182) but number of cabin crew did (4/6?). This seems to be that those that knew there may be a 'problem' were more susceptible to the 'problem'. It'd be interesting to hear if others (who didn't feel ill) also smelled the chlorine type smell. For it to be that bad that six pax and four crew feel ill but two doctors can beaver away attending to people again doesn't feel right.
Then there's the fact that despite falling ill, they all recovered very quickly afterward. Remove them from the perceived danger and all is good again.
It wouldn't be the first time in aviation history that a bunch of people went ill due to panic over something being wrong rather than there actually being something wrong. The DJ terminal in Melbourne a few years back was a case in point.
Anyway, I hope there is a rational explanation to all this. I hope there actually was something that caused those people to feel ill. Although either alternative isn't pleasant.