Having spoken to Ianto about Jack's anger issues recently, Deanna's been wanting to run into him, even in passing. She wants to see if his anger feels as strongly as Mal's did.
So that's why she turns up for the socialization part. She did help with the obstacle course, but she's not a combatant. She's a counselor and so she would have helped more with the puzzles and things of that nature. Whatever Jack might feel towards her for that, she still wants to at least speak with him.
"Well, that was certainly interesting. Data did a good job coming up with something so challenging."
At least she's wearing a pleasant smile and looks interested in a conversation. She's not looking for a fight here.