When he was demonstrating against pipelines in British Columbia, I wasn't so worried. He might have got arrested, but by Canadians who are mostly civilized. But the Israeli Defense Force is known for doing whatever they like (at least to Palestinians) and not always being held responsible. As it was, his arm got pulled and twisted pretty bad, but he's okay. From the videos on the links, I can see the IDF being pretty forceful.
Anyway, I knew what I signed up for.