You get this achievement during the poker game while under the guise of Farnham
After being interrogated by the barber you'll be playing with Cassidy and two other people.
You have to shoot down Quince (the bird) at every opportunity you have. This is what you have to say to him in order:
He Stands to lose!
There are better ways to educate children
Threaten to kill him
After this a cutscene plays and you should get the achievement
(Because you can't use your cat senses for this achievement it locks you out of "The Reaper" achievement, unless you restart the section again and assuming you've selected the right dialog options to kill Mary and have O'Leary kill Colbert beforehand.)