http://youtu.be/t-4r5NUuLAc
[Front-paged. -stabguy]
Setup
When you fight Rodrigo in sequence 11 there are barriers to prevent you from leaving the area. You can get past them by dropping down on a certain roof, allowing you to move past the barrier. However this causes you to be past a memory wall, draining your health and preventing you from getting too far away (better stock up on medicine and armor). Now for killing Rodrigo by drowning him. There are invisible barriers that prevent npcs from falling into the water. Here's how to get the target past these barriers: Go to the roof shown on the video and wait for Rodrigo to arrive. Then get him to go on a rope connecting two buildings and get to ground level. When the target gets to ground level he will be on the other side of the barrier. Climb back up and go to the higher roof. There are two paths Rodrigo will take to get to you. One leads him the way he came on the rope connecting the buildings. This won't work because it leads him back to your side of the barrier. The other path, however, will work because he stays on the other side. After drowning him the cutscene starts. But there's something different. Rodrigo isn't in the scene! For the next scene to start simply kill the guards who appear. After that scene more guards appear, along with some allies. The next scene can't start because Rodrigo needs to have his health taken down, and he's already dead. If you wait till then to drown Rodrigo the scene will start, with him missing of course, and you can progress through the game.
Messing Around Earlier in the Memory
After being disguised as a guard you can roam around freely. When you get within a certain distance of the lead guard he starts walking, and there's a distance restriction. Here's how to get around that. Throw at least one knife at him to move him away. Now you don't have to worry about getting so close that he starts walking. You can now go to Rodrigo without activating the scene. Rodrigo is invincible, and if you try using grab move he walks back to his spot. Plus there's a distance restriction to the box you're carrying, so an early death at this particular part of the memory doesn't look possible. But one thing you can do is remove the two guards from the scene. The game desynchronizes you if you kill any characters at this part of the memory, so you have to kill them in a way that the game doesn't recognize as you killing them. In this case push them into water.