HITMAN World of Assassination

First we need to make our way to The Block and grab a fuse to fix Hush's relaxing chair and some poison from downstairs. Then grab the subject's disguise from in the bathroom and talk to the doctor to start the experiment. Don't resist Hush's control. After the experiment ends, Hush will go to his relaxing chair and you can poison the ventilation system on the balcony.
Next, we need to make our way through Royce's lab and clear out the break room. Use our camera to send the other three employees on break and grab the screwdriver from Royce's office to sabotage the plug in the break room. Wait for Royce to clear out the break room and then puncture the water cooler to shock her.
Finally, restart and head to the rooftops to grab a sniper and shoot all the drones out of the sky. This will cause Hush and Royce to meet on a balcony and you can take them out with one shoot.

-To kill Hush in the relaxing chair, you must first require a fuse cell (found near the arcade and in the block), you must then go to the therapy room (top floor of the block), knock out both the guards and hide the bodys in the closet, then insert the fuse cell and wait for Hush to come in. His guard will leave the room and he will sit in the chair. You can ONLY get the achivement when he is sitting in the chair. After that. you can kill him any way you want to. I reccommend the katana which is sitting on the shelf.

- To kill both with one shot, follow the "All-Seeing Eyes" mission story. When Royce and Hush come out to meet each other, I recommed you make a save point as it can be difficult to make the shot on your first attempt. At one point in the conversation, Royce will stand infront of Hush and that is when you can make the shot, however, this is only for a small amount of time so be quick. If you follow this mission story correctly, you can achive both SASO and Sniper Assassin for this mission.

- To kill Royce with electrocution, equip yourself with some kind of a tazer or car battery, enter the ICA facility and find the water cooler outside one of the offices Royce goes into and puncture it. If done at the right time, no one will spot you. I reccomend that you also place a coin down so that Royce will walk into the puddle to pick it up. When she does, you can either activate the tazer or throw in the car battery. Word of warning though, if you throw the car battery in, you will be spotted and loose your Silent Assassin rating.