he must have known what his fate would be
That is very true, and comes out time and time again with the British agents shot by the IRA. That to me is quite incredible that they carried on knowing that they were almost certain to die. But the IRA knew that they too would die if they were caught.
With what I am doing with my research is trying to avoid a moral judgment on whether A or B deserved to die. It happened, and I am trying to see what actually did happen. A lot (most) of these events have just been ignored by history, and indeed even by the descendants of the men who took part.
What I am trying to see with Ryan is who was employing him. He undoubtedly had fingered McKee and Clancy the previous November. I suspect that it had taken so long to catch up with him was because he was being "run" by Basil Thomson out of London to avoid Dublin Castle leaks.
Ryan must also have been involved in other information being passed back to British Intelligence. That is the sort of collateral that one will just stumble across when looking at another incident altogether.
An interesting point about Ryan is that he appears to be a Dublin man, complete with a wife, sister (albeit a Madam) and a brother-in-law. Most of the spies did not come with that sort of pedigree. They were English or Irish officers living in rooms by themselves.
Thanks very much for the Paddy Kennedy quote. I look forward to Bill Stapleton's version which I believe will back up Kennedys. At that point I think I would opt for the Kennedy/Stapleton version!