The simplistic interpretation of the Finucane affair is that Sgt William McBigot from the RUC Special Branch met up for a pint with his pal Johnny MacMadDog of the UFF and passed a couple of 'names' on to him... Presumably Sgt MacBigot then left saying, "Remember Johnny/Ken/Billy/Jacko/Delete-As-Appropriate, that whatever happens after I give you these names, it's got nothing to do with me!"
It's a convenient cop-out which defies the already disclosed evidence about the level of collusion between British military intelligence, RUC Special Branch and loyalist paramilitaries. The loyalists could not have finessed their operation without input and direction from British Intelligence personnel such as Brian Nelson, who refined their intelligence operation and who selected targets for assassination by the UFF/UDA. Nor could they have carried out such operations without good and effective firepower, which they were supplied with via an MI5 gun-running operation from apartheid South Africa in the late 1980's.
The Brits and RUC Special Branch were not only in the business of recruiting touts in loyalist areas, but also of recruiting reliable assets with a penchant for killing taigs, who would take direction and be supplied with the 'names' of targets and the right gear for the job. Throw-in the amazing way that British Army and RUC units would just magically 'disappear' from the streets of the intended target's home area just before a loyalist death squad moved in and I think you have more than a series of unforeseen coincidences.