An actor would be foolish to do something that might hold up the picture, or more importantly incapacitate him. If an actor does do a stunt he needs to make sure a stunt man stands by to see that it's done correctly. ↗
In studio films, everything has to be boxed in, everybody needs to know beforehand - this is comedy, this is sci-fi, this is drama - and what's the point of independent film if you don't get to experiment? ↗