How about, the whole affair was carried out in the uk and not the US to remind Donald Trump about what happens to guys who betray the Russians.
Trump has not responded in person to the atrocity .... not like him, not even his "Thoughts and prayers"
If it had been in the USA and he hadn't reacted personally where would that have left him
As many have said in this thread it was done in a manner that gained the maximum publicity
Just a thought