Michael If I'd just listend to you five years ago... things could have been different.
Nikita Things will be different.
In the same episode:
Michael I came here to betray you.
Nikita But you didn't.
In 1x11 All the Way when in order to protect Alex after she failed to complete the mission Nikita lets Alex give her to Division so that she won't be cancelled
I suppose we all expected with the title of 1x21 being "Betrayals" that it would be Michael to betray Nikita after his recent switching to her side. It was kind of heartwarming to see the clip for "Pandora" where he told Birkhoff Nikita is right. Although, kind of Tear Jerker -y when Birkhoff tells him that Nikita's dead.
Michael's speech to Nikita about how he found the perfect home for his family, and how his young daughter would react. He tells her this after she helps him find and kill Karim Tariq to avenge the death of his wife and daughter.
The dinner scene with Dana and Charlie in 1x20 with Michael and Nikita posing as newlyweds and they are asked how long they've been married. Also heartwarming when Charlie asks how long it will be before they start "popping out the rugrats" and Nikita and Michael almost spit out their drinks.
At the end of 'Pandora' when Michael and Nikita are in the car together talking. They have a very quiet conversation about what's happened and what's going to happen. You can just tell how much they love each other in that moment.
In "Rough Trade" when Victor Han forces a kiss on Nikita and Michael snipes his bodyguards from a distance, allowing Nikita to escape.
"Game Change" was full of heartwarming moments. For example:
Michael: (To Nikita) You never said you were perfect. I did.
Alex doing right by the prostitutes she first looked to be screwing over to get back into Russia incognito, setting them all up with enough money to make a new life.
In the same episode (also, a thematic callback to 1x17):
Birkhoff to Nikita: I almost gave you up in there.
Nikita: But you didn't. You rule, Nerd.
Michael returning from London, leaving his son, because Nikita and Birkhoff need him.
Nikita comforting Birkhoff after he's forced to kill her mentor, Carla.
The entire third act of "Wrath." Michael surrenders himself to Brant not to save Nikita, but to see her one last time before they both die. He admits he's perfectly fine with dying as long as they're together. And don't cry just yet because it gets even better—after Sean and Alex save them, Michael confronts Nikita about her deep self-hatred in the following scene:
Nikita: (near tears) I said some unforgivable things.
Michael: Yeah. But you had to. I know it's not because you don't love me. It's because you don't love yourself. (he touches her face) And that's okay. I'm willing to teach you. (they kiss)
In "Shadow Walker," the last scene of the episode is spent with Nikita telling Birkhoff that he isn't just some worthless nerd; he's the backbone of the group, and is completely irreplaceable.
When the team learns Birkhoff has been captured, Nikita immediately abandons the plan to steal Percy's money in order to save him. She walked away from seventy million dollars to rescue Birkhoff.
The end of "Innocence", when Nikita and Alex bring back the kidnapped girl to her parents, and their subtext-laden conversation of how Nikita brought the last girl she saved home, and how it's Alex's turn to do the same.
The Season 4 premiere: Nikita is in trouble, in a major news corporation's HQ... and then Michael calls her to say he's here for her extract, and Birkhoff and Ryan are on the line to provide support.