Patrick Jane was the last to know that Teresa Lisbon was leaving for Washington D.C. in a week on The Mentalist Season 6 Episode 22 which is probably why he hadn't been trying to change her mind.
But when a letter opening a high profile cold case turned up, Lisbon's transfer was put on hold as she and Jane tracked the lead to a romantic hotel on the beach. Unfortunately it didn't take long for Lisbon to figure out that it had all been a ruse. Jane had sent the letter himself because he didn't want to see her go. When his plan came to light, the whole thing backfired and Lisbon was furious.
She was so angry that she fled to the airport to catch the first flight to D.C. and marry Marcus Pike. When Jane realized he would lose her forever, he gave chase. Thwarting security, climbing a fence and bursting onto the plane Jane professed his love, even if it was too late. Then TSA officers dragged him away.
Still being held the next morning, Patrick was shocked to see Teresa come to his rescue and admit that she loved him too. In response, he leaned across the table and kissed her.
If the romantic in you wants to see it all again, you can watch The Mentalist online right here at TV Fanatic.