Or, she thinks, if it had been that simulation Jeanine had used on him in the Abnegation headquarters, he wouldn't be thinking about a longer kiss. He'd think she was the enemy again and he'd be doing his best to kill her rather than kiss her. She thinks that she likes his version of a simulation better. No. There's no doubt. She definitely likes his version a lot better.

Suddenly, she doesn't want to think about serums or simulations anymore. Even joking about it starts to trigger that guilt that brought her up to the to roof to begin with. She had shot Will because he had been under a simulation and would've killed her. She hadn't thought twice about it. Now it's all she can think about even held safe in Tobias' arms.

She slips out of his arms without another word and starts to walk back towards the edge, keeping her back to him so he can't see the conflicting emotions on her face.