Easy "Silent Assassin" rank on "Till Death Do Us Part"
Only two poison syringes are required. At the beginning, head towards the party and wait for the drunk guest to vomit. Go to the shed on the left and follow him into it. Wait for him to sit and fall asleep, then take his party invitation. Go to the main house and enter. Stay to the right of the stairs. If the bride is there, do not talk to her as this will take your time. Instead, keep going to the end of the foyer. To your right is the kitchen. Check your map to make sure no one is in it, or is going to it, or is behind you. As soon as it is clear, go in the kitchen and use the poison syringe to inject the wedding cake. Go into the room directly behind you while staying next to the wall so when the priest enters, he will not see you. Wait for the groom to come into the kitchen and take a bite from the cake. He will die at the kitchen door. When you are clear, go back in the kitchen, drag his body, and hide him in the container at the corner of the kitchen. Get out of the kitchen using the same way you came in, then go straight for the bathroom. Making sure no one is in there, pick the lock on the door next to the toilet room. Do not go into the reception area. Instead, keep going straight to the bathroom. To the left is a door that is locked. Make sure no one is in the bathroom and pick the lock. There is a guard patrolling the next hallway. Make sure he is walking away from the door as you open it, then run straight for the door in front of you just to hide for a little while. If you think you are fast enough and can make it for the stairs before the guard turns around, do that instead. Go up the stairs and to the left, staying as close to the wall as you can. There are guards just around the corner as you enter Pappy's room through the door left of the stairs. Go in the room and find the area where the TV is located. Get your syringe out and ready and enter the closet. It is now just a matter of waiting. Pappy will eventually come up to the room to watch television. Come out and give him a dose of poison. Then, go back down the same way you came up. Make sure the guard does not see you coming down the stairs, as no one is allowed to the second floor. Use the same way to get out -- through the bathroom, then directly to the outside. Walk, and do not run. Also, if you suited the drunk guest, put your suit back on to avoid the overages of suit retrieval. If your bar is a little yellow, it is acceptable as you will still get the "Silent Assassin" rank.