"reached maximum characters [...]
While she is "okay" with him hurting her, he never lets her see what he actually does (except for the time when he killed their father - but she rationalizes this by him deserving it for hurting her). So he realises that he needs to get home with Hotch because he does not want to ruin his "good" relationship with his sister. The important point is, the mentor's inability to truly understand how his sister feels, but Hotch does and although he is probably in the worst situation since the end of Season 4, he knows he has to try and get the sister to help him. So it is kind of a battle of the wits between the mentor who is also highly intelligent but devoid of true emotion and Aaron.
Although naturally the team who realise pretty soon, that they got the profile terribly wrong, still do not know that the other sister is alive and that they probably not going to see their leader again unless a miracle happens. I already know how it is going to end but I think I keep that secret for now ...

Forgot to add: It would be nice if someone who lived in Texas or the South of the United States was interested, someone who just beta-reads would be lovely but even more I would appreciate it if someone willing to work through the scenes with me, giving direct feedback to dialogues and difficult situations would like to work with me on this."