Even though you and Emily have never been on friendly terms, that's exactly what made you two know eachother so well. You knew eachother's nervous tics, upset expressions, tones of voice.
This case was a particularly bad one. It had awoken memories you would rather have kept buried deep. Along with that, it was in your nature to push people away when you need them. You didn't accept help, you thought it made you weak.
On the way back, Emily noticed you sitting in the far back away from the sleeping members of the team, wide awake. Despite her mind screaming at her to not do it, she didn't want to deal with you right now, she walked over and sat down across from you.
"What's up?" She sighed, expecting some playful remark. But when you replied with a harsh "why do you care? Go away." she was.. confused. Sure, you two didn't like eachother, but you always humoured her.
"Morgan told me you've been more of a jerk lately. What's going on?" Maybe she could push her rivalry to the side, just for this night.