JUST how frantic is “Noises Off”?The action is so fast and furious in Michael Frayn’s farce – about a poorly rehearsed group of actors – that the actual troupe’s been injured as well. Here’s a partial accounting of injuries since rehearsals began Sept. 10:

* One scratched cheek.

* One puncture wound.

* One bloody finger.

* Assorted bumps, bruises and scrapes.