I did the same - he had a sprint about the 42nd minute, only a short one but not the sort of thing he could do if he had a significant tear, and he didn't pull up. After that, as you say, he jogged around looking comfortable enough, and walked off normally at half time.
Even though he's a tough bugger, as has been said, there's no way you can even jog on a serious tear - you just can't hide that sort of thing.
Jose was mad at the world when he gave his comments, giving one word answers etc. I wouldn't be shocked if this was just his frustration coming out and Son's injury's not that bad. Fingers crossed.