Still doesn't change that the revenge was his daughter dying which would not have happened if Harry had failed.
That was what Tessa thought. But I think she was wrong.
I think Nicodemus had the Genoskwa as backup for Harry for the ice gate, with the coin he had not that much difficulty in following Harry through that gate until Harry started to play dirty. And that was after Grey had mutilated him.
And Hannah with Lasciel was the other backup for Harry. That was why he still tried to kill Harry even after he had closed the gate, Nicodemus had backup for that as well.
So I think that even if Harry had failed with the ice gate the Genoskwa would have handled it and after that Deirdre would still have died. Nicodemus is too experienced not to have a backup plan for Harry.