I was always impressed by Daniel Hill's ability to act physically. There's two or three instances where he tripped or fell or somehow threw himself about in a way that most actors would be afraid to do. For example, when he tripped on the go-kart, or when he was clotheslined while jogging.
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"We don't need more good speakers
We just need more good men speaking"
I think that while he (and Diana) did some of their own stunts, for instance Diana's fall at the fashion show and Harvey's fall into the mud when he is jogging and is hit by the bundle of Sunday papers. I believe that a number of the incidents were actually done by stunt doubles, in particular, the clothesline scene. I think the tell is that they never show his face and the actor actually covers his head with his arms as he falls and after he lands. Antonio seems to do many of his own falls, however.
Good catch!
"It's a real burden being right so often." Captain Malcolm Reynolds, Firefly