She only brings up the swimming after she has agreed to give Isom her phone. She is telling Isom that her last communications with Danny were "not nice". Her explanation for this was:
Wendi: “yeah, I’m just looking here (flips through phone). I didn’t want him to take the boys this afternoon. I had wanted to have them. And I talked it over with my brother and realized, you know, if their Dad wants to take them swimming, it’s not worth getting upset over.
Back up a sec here. Dan is leaving for NYC the next day and won't see his kids for a week. Despite his best efforts, these two are not positively co-parenting with each other. She's not complying with Skype calls with Dan on the weeks she has the kids. He invites her to kids events when he has them and she never does. She just sabotaged him about the school and she wouldn't even pick up the phone to discuss it with him. All week. And here she is, asking if she can pick the kids up early on his last day with them. And very upset when Dan tells her no. It makes ZERO sense. And then she suggests that Charlie, of all people, who we now know has killers circling Tallahassee calmed her down and explained to her that Dan taking the kids swimming is not a big deal. Give me a break.