[Completely silly mode engaged]
Nah, you see, this is really a plot to get Lara killed, because Mab wants to eliminate any competition before she makes her own play.
First she used her Proxy Lea to arrange for Susan to get caught up with the Red Court in Book 3, Then in Book 4 Mab shows up to introduce herself and save Harry's Bacon to catch his interest, This sadly didn't work.
Moreover, a year later Susan turned up in town again and hooked up with Harry, even getting with Child, thus sealing her fate- she was a threat again, so Mab arranged for the Red Court to be sacrificed to kill Susan and get her out of the way for good. She also arranged for the attack on the Raith deeps in order to get rid of Lash, who was becoming another major threat.
Once she has forced Harry to come to her in changes she thought she could try winning him by helping nurse him back to health, but somehow that backfired and he seemed to be getting along with Sarissa instead! This forced her to adjust her plans, and she arranged for the death of Maeve and Lily to get Sarissa and Molly out of the running, only for Harry to hook up with Murphy instead, thus forcing the events of Skin Game to try and get her killed, and latter Peace Talks/Battle Ground when Nick failed to kill her.
Now, seeing Harry and Lara getting along so well, she's going to try and force them into something, knowing that Harry will chafe at it and oppose the match on principle, and Eb will probably kill her if he doesn't.
Don't give up Mab! We believe in you!
Truly, the Dresden Files was a tragic love comedy all along.
[end completely silly mode]