I got the above a bit wrong. Re: "Don't try to grow a brain John." Patsy puts a comma after "brain" on pass 2 of the first session and pass 1 of the second session (which is after her lawyers have been given a xerox of the ransom note). The other two sentences don't have commas on any passes. That tells me she knows a comma is grammatically correct. It could be argued that she's careless about it, I suppose.