Assassin's Creed Revelations Walkthrough Part 44 – The Exchange, End of the Road

The Exchange
You are now being actively hunted by every partol in the city. Your best bet of making it there is going to be through using the tunnel system. Head for the Assassin's Headquarters to start the memory.

Full Synchronization requires that you rescue Sofia before she loses half her health.

Start the memory and head out the door. You need to collect some Assassins to ensure that everything will go as planned. Head for the marker in the Galata Graveyard to progress on with the memory. There you will collect your assassins.

After that you will encounter another cutscene. Ahmed has Sofia captured and held on the ledge above on Galata Tower. Scale like there is no tomorrow to make it there in time. You have two minutes to make it up which is not too hard to pull off.

Once you do make it up, you need to get back down in a hurry. Use a parachute and aim for the next marker. Just ride the parachute as far as you can, drop at the last moment and dash over to Sofia and interact with her to save here.

End Of The Road
Full Synchronization requires that you kill 20 guards.

Time to wrap up another memory sequence. You are back on a carriage with Templars on both sides. Ramp them into the unstable terrain and keep more to the center yourself. Destroy the pair to progress forward in the memory.

When the next cutscene begins, pay attention. You are now attached to the carriage with a parachute. You need to protect Sofia by swooping in and assassinating the guards that are coming in. Throws are the most effective, as you direct them and they take out two guards at once. Just be sure to line up with the first target then go at them. It is not too hard to the Full Synch condition.

Now you fight Ahmed in a very different fashion. Use your high profile to defend and primary attack to punch Ahmed. Defend when you see him draw back his arm to strike at you. Once you make it through this sequence you are done with memory sequence 8.