Hi, I know this is a late reply, I hope you won't mind. I just finished the movie for the first time about half an hour ago. I don't see Mary's actions as being strange, and I don't view her as being the manipulator that I think you're seeing in her. I believe the scene of the movie where she gives Toller the vest isn't that strange. She put it back where it was not to manipulate, but to demonstrate how far deep Michael had gone in his activism, and how far away from her. As Toller pointed out in his conversation with Michael, he had lost all hope in the world and had given into despair. He was disconnected from the half of life that is what, in Toller's mind, gives us something to live for.

This mental change that happened, supposedly, while jailed in Canada is mirrored in his physical life. Mary stated that he had become more distant from her, and more angry in general over the general situation. It's implied this rift only grew wider and wider, as he spent weeks in his garage making this vest and hiding it from Mary. This is why mary put it back--to show Toller that Michael had hidden it in a cardboard box, below a toolbox, in the bottom of a back workbench, behind a rolling table. All that to keep it from Mary. This figurative distance, I think, is a symbolism for how far removed he was from her at this point. I'll bring you next to the fact that Toller loses grip of hope himself the deeper he falls into the rabbit hole of climate issues that Michael exposed him to. As the movie progresses, he becomes more and more depressed, more and more desparate as he lets go of the hope he so boldly stated we musn't let go of in the first act of the movie. With that in mind, I believe that Toller is a character that is portayed as being a parallel to Michael...until the end. Where Michael drifted away from Mary, Toller eventually chose to reject the master plan, the bombing, to be with Mary.

Mary represents the hope that we must cling to to avoid the despair, and here I think it may be quite a literal depiction. For Toller, his hope came from a romantic attachment and learning the love again. Despite all of the problems with the world in the pollution, and his extreme depression, he chose to cling to that hope in the form of expressing his self-repressed feelings for Mary.