Your extraction zone can be selected only after killing both Viktor and Dalia and has no effect on the result of the mission. The only exception is by evacuating with the motorboat, which will award you with an achievement associated with the described mission. Selecting an extraction zone should be dictated by your actual position on the map, and whether Agent 47 is wanted by the enemies. In the latter case try to select one of the closest and unprotected extraction zones.
Available extraction zones are:
- Gates on the eastern section of the map - one of these is the one you've started the mission at (point M3,1 on the map).
- Entering the catacombs in the basement (which can be seen on the above screenshot) (point M3,32 on the map). This is quite an interesting extraction area, as it is unprotected and it does not require you to have any special items (such as keys to the building). Use this extraction area if it's the closest one to your current location, or if the enemies are looking for Agent 47.
- Helicopter on the landing back behind the palace (M3,10).
- Speedboat on the Western edge of the map (M3,11). Using this extraction point is very complicated. You would have to start by visiting one of the rooms on floor 2 and finding the Speedboat Key (M3,11) (it's on a desk shown on the screenshot above). Once you have the key you can proceed to the motorboat. It's being protected by a single guard, however you can easily subdue him or sneak past him when he starts his patrol.
Important - If you've decided to go get the motorboat key then there's a chance that Agent 47 might have been recorded by one of the palace's security cameras. If that happened you should visit the monitoring room on floor 0 (M3,17) and destroy the recordings.