A question for anyone who has an opinion: when do you think Camille 'switched sides' from following orders from Silo 1 to throwing her hope and hidden support to Juliet's team?
I've seen a fair bit of interwebs traffic posit that the Vitamin D barrels were swapped out at some point in their trek to the Water filtration level but I'm not sure I buy that (or at least, if they were swapped, it wasn't at Camille's direction).
Second, a swap of tanks is exactly what Camille did do with the rat poison/O2 bottles so that would be lazy writing if they went to that well twice and the writing on the series has been excellent so I doubt they did that either.
Which is all to say, the seeds of doubt were sown in Camille's mind starting with Bernard (which was his intention along with serving as a distraction), and I think it was literally when they saw Bernard die from the cafeteria and the dynamite went off, Camille realized then and there that they were all dead so may as well buy Juliet's crew some time because they were literally the only option that remained for survival. I just can't think of another point in the story where she could have switched sides but would love to hear what others think.