I think the key here is the lady that attacked Patrick with the knife. she was sent by RJ, (maybe) not to kill Patrick but to save sheriff Mcallister's life. When she walked in, Mcallister yelled "help, he is going to kill me" like he didnt know who was there. if he was red john, he would have like a escape plan or something.

Even if he was RJ and his "escape plan" was that guy oscar, what is with the lady? who is she? 

I also though that, ok maybe everything isn't this complicated, and Mcallister is RJ, but after Patrick hit the lady, Mcallister ran out and patrick went after him, after that  we saw the lady leaving, she didnt go to save Mcallister's (RJ) life, (what i think should be the priority doesnt matter if she get caught, or even killed) she just took off like it didnt matter anymore, like the plan fall. 

Just a theory, comment what you guys think, i'd like to see your opinion... BTW: Sorry for my english, is not my native language.