if the country is Pakistan, yes it is quite easy for a well planned operation to get in and out. Mind you Pakistan has some VERY smart military officials (some smarter than a majority of westerners I have seen) but these officials do not agree with top military leadership which is totally half political, a quarter feudal and the rest religious zealots. Therefore the smart ones keep their mouth eyes and ears shut and do the minimum necessary to comply. With that background, add the fact that the USA had just had 7 out of 10 missions compromised in the prior 4 months - that led to a natural decision that Pakistan will not be trusted and the operation, instead of in collaboration, will be conducted in spite of military intelligence including ISI.
Contrary to popular belief, ISI had by then (in fact a couple of years before) become an 'execution' organization that meted out clever punishments (aka extra judicial internal operations) and ceased to function effectively as a spy force. That status continues todate with an additional mandate - to be relationship manager and arbiter for feuds amongst different 'jihadi' gangs.
Almost all the internal bombings in Pakistan for the last 4 years can be traced to one or more such ISI led arbitrations where one of the parties did not like the verdict and decided to show power.