This achievement is a "conversation achievement". It is straightforward enough to get this achievement first time. Wayne Haas is an old squadmate of Jensen from his SWAT days, and has been suffering from guilt due to actions taken in the massacre. He blames Jensen for all his misfortune, especially that he is now just a 'desk sergeant' . You must somehow talk Wayne around into letting you into the station. The first answer is always Absolve, but after that the conversation is completely randomized.
Being sympathetic and nice is the best way to get through this section; you must convince Haas that he isn't to blame for the child being shot in the massacre. He will ask you to tell him outright that it isn't his fault. Once you've done that, he will back down and open the door for you. The achievement will unlock once this happens.
Interestingly, the exact opposite can be true. If you continue to act aggressive, there is a chance he will back down. As long as he doesn't say that the incident was your fault, you can continue to pressure him without the need of an augment. When he pleads with you to tell him it wasn't his fault, refuse and he will let you in.
If you have chosen the C.A.S.I.E Social Enhancement Augmentation as one of your augments at this point, you can use it to bypass the conversation completely once the prompt is given. Wayne Haas is an Omega Type personality and will react to pressure. However this is EXTREMELY ill-advised as it will cause him to attack you in your apartment later on in the game.
- Threatening Wayne may cause him to attempt to attack you at your apartment building later in the story.