'Criminal Minds' Boss on Plans for 300th Episode and Finale Twist: There's No Winning (Exclusive)


Showrunner Erica Messer talks to ET about the dramatic season 13 finale cliffhanger.

Warning: Spoiler alert! Do not proceed if you have not watched Wednesday's two-hour finale of Criminal Minds.

We're officially worried.

On Wednesday's finale of Criminal Minds, titled "Believer," the BAU team members discovered that Agent Owen Quinn (guest star James Urbaniak) wasn't the agent they should've been worried about during his year as a hostage. It was Special Agent Mary Meadows (guest star Karen David) who turned out to be a member of the cult led by The Messiah, currently locked up by the BAU.

The final scene ended on a cliffhanger when Agent Meadows pulled out her gun and pointed it at Reid (Matthew Gray Gubler), who had put the pieces together a minute too late, and gave him an ultimatum: Join them and help get The Messiah out or Garcia (Kirsten Vangsness), being held hostage by The Messiah's followers at gunpoint, dies. So what is Reid's next move?

"He probably has five game plans happening in his head in that moment, as he's holding the gun at Meadows," showrunner Erica Messer tells ET of the season 13-ending cliffhanger. "Because what he won't do is anything jeopardizing Garcia, losing her life and being hurt in any way. He's trying to figure out 'What do I do? What is the bigger plan here? Why do you need The Messiah out?'"

With Reid faced with making a difficult decision, there's a very good chance that "given that choice, we know what Reid's going to do because he's certainly not going to let Garcia die," she says. "The argument is still there that he's there holding a gun on Meadows, who's holding a gun on him, and there's somebody else holding a gun on Garcia. There's no win right there if everybody pulled the trigger. It would be horrific."

In the finale, Special Agent Mary Meadows (Karen David, center) is revealed to be the agent who's turned and part of The Messiah. - CBS

Though Criminal Minds has yet to be officially renewed for a 14th season by CBS, Messer revealed that the writers are already "talking about what that next episode would be," which would mark the series' landmark 300th episode.

"There are many different ways to go, but, obviously, we want our wonderful heroes to be in the 300th episode," she hinted of the upcoming premiere, if the show earns a renewal. "It would probably be a matter of our team trying to solve one of the biggest cases they've ever seen without two of the most important players on their team."

Messer addressed potential worries that Reid could find his way back down the rabbit hole, if Meadows lures him into the cult with an intriguing enough offer.

"It's not about Reid joining the cult as a cult member, it's more helping Meadows release the leader," Messer says. "I don't think we would ever believe that Reid would ever sacrifice his belief system to be a part of a cult, but if he feels like, 'I'm doing the wrong for the right reason,' that's something that he's justified before in his time away in prison, even. Sometimes you have to bend the rules to do the right thing."