When I read your original post I felt sorry for the poor little might b/c I thought the same as you.... However when others have posted their own situation with their own kids then I realised that maybe she did the right thing b/c maybe he does get 'out of control' with that seemingless type of play.
I love it when DD runs around pretending she is a dinosaur, dog or otherwise but I do admit I reign it in when out in a public place, particularly if others are around. I usually just tell her to turn the volume down a bit & I discourage screaming.