Yates (spoilers)

When did Yates join Irwin's crusade? He turned down the invitation and seemed to stay on the outside until Winter asked him to inform on them, then he was included in the planning of the overthrow altho some did not trust him (Irwin did), then he took the flag from Winter's office (which we don't know until later). Was he tasked with getting the flag or was that his own spur-of-the-moment decision? Was his seeming outsider persona a fake at the point where they are planning and he is included, or did he just get fed up with Winter when he was in his office? Did his comment about "Where do you want me?" serve as his acceptance of the crusade, or had he been a plant all along? Did Irwin trust him because they had some unknown (to us and the other inmates) agreement or was he still trying to get him to join?

I've only seen it once and missed a few spots, so if I missed something that explains all this please don't tell me to pay attention.

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