The break up

The argument

Tim and Lucy are walking out of the station together.
T-"Way to pull off the fourth-quarter win"
L-"Thanks"
T-"What?"
L"Nothing"
Tim grabs Lucy's arm to turn her to face him.
L-"Nothing"
T-"This isn't gonna work if you're gonna lie to me"
L-"Fine"
L-"Did you undermine me today because you're scared that l'm gonna make detective?"
T-"What? No"
L-"Tim"
T-"No"
T-"And I'm upset you'd even think that"
L-"Look, I don't know. Maybe it wasn't deliberate. Maybe it was subconscious"
T-"So... so now you're accusing me of being unaware of my actions?"
T-"That... that's not better"
L-"You have to admit that what happened with Isabel was deeply traumatic for you"
T-"I've never not admitted it"
T-"I admitted it the first day we met, okay?"
T-"So the only thing I did today was have your back"
T-"But i-if you can't see that, then..."
Lucy looks at Tim scared that he's gonna suggest that they break up. Luckily Tim stops him self from saying something stupid like that.
T-"You know what? I'm tired. You've got studying to do"
T-"So let's just take the night off. All right? I'll see you tomorrow"
Tim walked away and Lucy was stood there shocked. Lucy got in her car and started to cry. She had all of these thoughts going through her head. She drove to her apartment and went inside. She tried to be quiet so Tamara didn't know she was crying but Tamara knew.
Tam-"Lucy why are you crying? What happened?"
L-"I messed up, I was overthinking about the detectives exam and now I've messed up my relationship with Tim"
Tam-"I'm sure you haven't"
L-"No I have"
Tam-"Do you want to go and see him, talk it out with him"
L-"I don't think he'll talk to me. He wanted to break up with me"
Tam-"I don't think he does"
L-"I think he does, but I don't want to be broken up with, it's the worst feeling, I'm gonna break up with him first"
Tam-"Lucy don't say that, you love Tim and he loves you, you guys are like the real life Meredith Grey and Derek Shepherd"
L-"Well Tim isn't dead and he doesn't have a wife while he's dating me"
Tam-"Thanks for the technicalities"
Tam-"Let's watch a movie and play board games"
L-"I like that idea, thanks Tam"
Tam-"Your welcome Lucy"
They both watched movies and fell asleep on each other.

~With Tim~
Tim walked to his car and drove to his house. He walked inside and grabbed a beer and slumped onto his couch. He had so many thoughts going through his head.

What would have happened if he said they should break up? Why did he almost say they needed to break up? Does he really want to break up? Why did she bring up Isabel again?

After 3 hours and 6 beers later he got up and went to have a shower before he got in the shower he asked Lucy if they could talk.

~With Lucy and Tamara~
Tamara woke up to the sound of Lucy's phone.
Tam-"Lucy your phone"
L-"Pass it here"
Lucy looked at her phone and saw the message Tim had sent. She replied with yeah but let's do it in person, did you want to come here or I go to your house or we do it tomorrow at the station. Tim surprisingly answered straight away saying tomorrow at the station. Lucy and Tamara both watched more movies and went to sleep