A very simple achievement, that will require you to play the mission 3 times to complete.
Eliminate Reynard While Orson Is In The Shower - The easiest way to do this is to hide inside the dressing room when Reynard says that she's going to bed after the phone call. Orson will go into the shower and the steam will block his view which allows you to walk up and assassinate your target. Make sure to drag her into a hiding place so she doesn't get found. Here is a video guide:
Eliminate Reynard With A Pillow - Similar to the last one, except this time you're actually going to let both Orson and your target do everything they need to until they fall asleep. You will also need to collect the
rubber duck from beside her bed so you can do this. You will need to give it maybe 30 seconds after they have laid down in bed till they are asleep but afterward you can smother her with a pillow by walking up to her. Here is a video guide:
Eliminate Reynard From The Roof of The Panic Room - This is the most challenging out of them all but the way I did it had some pre-planning. First, grab the
Rat Poison down in the pantry then head upstairs to the panic room and grab both
frag grenades and the
lockpick. After starting the encounter where everyone comes into the house, head on down the panic room steps into the garage, knock out the guard and
steal his clothes. Now head through the pantry and up the stairs to the roof. Knock out or kill both these guards then throw a frag grenade down to where the cars are. The enemies will find the body which will cause the target to go into
Lockdown so both Reynard and Orson will run to the panic room.
Use the
rat poison on the vent and give it some time to kick in, then
throw a grenade at the cover on the roof which will allow you to see her and kill her quickly. This will unlock the achievement if you did them in this order. Here is a video guide: