If the alleged reappearance of Kirkland (which could in fact be his twin brother) in 6.6 happens to be a flashback, it could turn out to be screenshots of incidents narrated by Jane revealing one of his tricks to trap a suspect. If that is the case, here's a plausible scenario.

Between the time when Hightower and Lisbon arrive to rescue Jane and the time when Kirkland is carted away, there is plenty of time for scheming. Jane and Kirkland both know that his life is probably in danger and they might not have time to discuss details of the TT organization. 

So, Jane plants a bug on Kirkland. The final conversation between Kirkland and Smith is recorded. When Kirkland runs, he ditches the bug so that it wont be on his person when they examine his corpse. 

If it does not happen in this way, then we have more information (crucial information) than Jane does at this point and Jane will have to learn the pertinent info on TT in some other way.

I think the show was supposed to get over at season 3 itself after carter got killed. He did fit 'red john' description perfectly.

I think the plot after that season is all bull shit.
And also, the recent Mentalist episodes season 4 & 5 (those without red john) were very boring. Jane's logic and "his memory castle" not so impressive like the first 3 seasons.

First of all, I do not watch the Mentalist. I'm bored with a little bit of free time, so I'm willing to show anyone who meets me in the comments section who Redjohn is, with answers to all of your Redjohn plotholes. I've only ever watched 10-15 episodes and Youtube clips (all featuring Redjohn). This is a closed affair, I can't handle more than 5 people, so please make this implausible.