I loved it because it felt like poetic justice. Wilf had got that far by using his traitor knowledge to expose other traitors. Then, with Kieran, he got hoisted by his own petard. Because Kieran actually made use of the fact that Wilf had exposed him...the only reason they believed Kieran was because Wilf had convinced them he was a traitor.
If Wilf had stuck to the agreement this time, they might both have made it out by accusing Aaron...or Kieran might have felt enough goodwill not to bring Wilf down with him. As he said at the round table, there was nothing he could do to save himself at that point because they'd all already made up their minds before they went in. Making too many enemies is always a risk.
I wouldn't be at all surprised if the producers had a hand in it, but honestly I don't care. Such a great arc.