My reading of it is that the kidnappers were radical units making a retreat in force from the Swat Valley--where they have recently taken a drubbing (they've been "swatted"--possibly by a Special Weapons and Tactics squad?) I think they took the kids, opportunistically, in order to create a diversion to allow them to escape back to South Waziristan. Most of the kids were released, in order to create more confusion to allow the principals--still holding a smaller number of the hostages--to retreat further.
I'm thinking this was a close call for them, with possibly some high-value targets of ours involved.
OK, maybe the Pakistani forces had their Tora Bora moment, or maybe not. Either way, I still salute them for their sucesses in routing their internal enemy. It was critically important to deny the Taliban a significant safe haven like the Swat Valley was being set up to be for them.