OK just look at how this "deal" is constructed -- the US will "investigate", in other words the Pakistan government accepts that it cannot "investigate" bu instead the US can, if the US investigation reveals behavior incompatible with Mr. Davis's mission, then the US may initiate legal proceedings - that is to say the government of Pakistan gives away (as if it was something it can give away) it's responsibility to uphold the constitution of Pakistan and instead relies on the US to do this.
Friends, every way you look at this, in the end you'll come against the Izlum of the Islamcican -- it is not a coincidence that the protesters are mullahs or are bing led by mullahs, after all, many are hiding their actions behind the behavior of the Mullahs, you follow?.
And then of course, with this action, questions about how come those responsible for counter intelligence were or have been asleep at the wheel, questions about how this whole thing came to be accepted among Pakistani security officials and many more questions, will now not be asked -- unless of course some section of the public makes it their business to ask