"just the execution"? What's left outside of the 'execution'? Allowing untold foreign fighters, spies, huge money to come to Pakistan while hurling fire at a Super Power occupied Afghanistan and brainwashing untold number of people to 'train' to blow themselves up in Afghanistan--never mind some of them would eventually be 'co-opted' by Pakistan's enemies to harm Pakistan itself--which they sure did and are doing till this day.
And, yes, allowing money loaded foreign spies to come in huge numbers inside Pakistan to set up the network of Jihadis was going to inevitably lead to at least some of them staying behind or finding 'moles' in Pakistan. The Pakistan of 1979 was different from the Pakistan of 1989. In just 10 years, perhaps no such large nation changed so much as Pakistan did in human history!!! At least I can't find an example in modern human history. A Sufi-oriented Muslim nation turned into a hotbed of fanaticism, of rented-Jihadis, political parties deeply compromised by foreign money, and indeed a country full of moles and spies.
Having said that, I have never questioned Zia ul Haq's financial integrity or his 'patriotism'. He was, like Mullah Umer of Taliban, just another religious fanatic but without a beard.