In rescuing Thomas as a favour, it will be in accordance with the Mantle DESPITE Mab’s publicly professed position during the peace talks themselves. This is why Mab did it, she can manipulate everyone without telling a lie.
Remember that Luccio knows about Thomas, I think this is the major betrayal, she tells the Merlin and he sets up the situation where Harry and Eb have to throw down over Thomas. What neither Luccio or the Merlin know is that Eb is Harry and Thomas’ grandfather. Mab knows, she is engineering this confrontation to cause a split in the White Council, probably to get rid of Christos and the Merlin, making Eb the new Merlin or the formal creation of the Grey Council as a new supernatural nation under the Accords taking Eb, Harry, Listens To Wind(I can’t help thinking this is a Blazing Saddles joke by Jim) Martha Liberty the Paranet and all the young wardens with him, splitting off the new world from the old.
The tag team of Lara and Mab suggests this type of machination by Mab, remember she had her own daughter killed in a similar circuitous fashion, and destroyed Nicodemus in a similar indirect fashion. I suspect one of the favours was Lara introducing Mab to Marcone prior to Skin Game as being interested in revenge on Nicodemus.
