Stop looking at it from the perspective of ethnic dividing lines - that's not going to help anyone.
Instead look at it from the terrorists' point of view - is there an advantage in having active cells running in Karachi? ** Of course. They've probably been there for a long time, and I would not be surprised if part of their funding is indeed coming from the robberies that are rampant in Karachi.**
Please don't accuse Holy Alliance of MQM/PPP/ANP of any such thing. No way no how! :D