If you choose to stop Marchenko first, keep in mind that you have about ten minutes before the delegates drink their poison cocktails. If you broke into the bank vault for mission 12 and got the antidote, that can be cured though.
Step 1)Stop Marchenko.
It's time to run back the way you came, if you didn't raise any alarms on your way to Miller, this will be smooth sailing, but otherwise you'll have to sneak or fight past some stragglers. You're heading all the way back to the party where you took out those guards quietly to continue. Marchenko has made sure there is nothing between you and him to slow you down though, how nice of him. He's more interested in facing off against you himself. When you do get to him, he doesn't exactly fight fair though, he'll have several police drones buzzing about that you'll have to either deal with or avoid. I found the best way of dealing with Marchenko was to toss out an EMP mine on a surface you know he'll be walking past eventually, and being patient. When he does eventually walk over the mine, charge in and perform a takedown on him and you'll now get to enjoy your ending without having to deal with those drones.
Step 2)Enjoy the ending!
If you've already stopped Marchenko, then you can sit back and enjoy the ending at this point, it's been a long trip and you've earned it. Stay tuned to the news broadcast and you'll see a summary of all the side missions you've completed being reported on as well, it's interesting to see how Picus spins the stories so horribly wrong.
OR
Step 3)Save the delegates.
You'll have to head back to where you found Miller and then head through the door you didn't come through and make your way to the elevator at the end to stop the delegates from drinking the poison champagne. The first hallway you end up in is going to have a turret and several guards. If you can manage to sneak behind the turret to the terminal behind it, you can actually turn friendly fire on and watch it gun down several of the terrorists while you can continue on your way to save Brown. If you gave Rucker’s evidence to Alex, the backtrace they did on the IP will light up with a brief connection, and a message will be passed that includes the password for the door to the meeting room: 2202. You'll need to get to the heavily guarded elevator to get to the delegates though. Utilize either your stealth skills, or gun your way through them, it's up to you how you do this.
Step 1)Stop Marchenko.
It's time to run back the way you came, if you didn't raise any alarms on your way to Miller, this will be smooth sailing, but otherwise you'll have to sneak or fight past some stragglers. You're heading all the way back to the party where you took out those guards quietly to continue. Marchenko has made sure there is nothing between you and him to slow you down though, how nice of him. He's more interested in facing off against you himself. When you do get to him, he doesn't exactly fight fair though, he'll have several police drones buzzing about that you'll have to either deal with or avoid. I found the best way of dealing with Marchenko was to toss out an EMP mine on a surface you know he'll be walking past eventually, and being patient. When he does eventually walk over the mine, charge in and perform a takedown on him and you'll now get to enjoy your ending without having to deal with those drones.
Step 2)Enjoy the ending!
If you've already stopped Marchenko, then you can sit back and enjoy the ending at this point, it's been a long trip and you've earned it. Stay tuned to the news broadcast and you'll see a summary of all the side missions you've completed being reported on as well, it's interesting to see how Picus spins the stories so horribly wrong.
OR
Step 3)Save the delegates.
You'll have to head back to where you found Miller and then head through the door you didn't come through and make your way to the elevator at the end to stop the delegates from drinking the poison champagne. The first hallway you end up in is going to have a turret and several guards. If you can manage to sneak behind the turret to the terminal behind it, you can actually turn friendly fire on and watch it gun down several of the terrorists while you can continue on your way to save Brown. If you gave Rucker’s evidence to Alex, the backtrace they did on the IP will light up with a brief connection, and a message will be passed that includes the password for the door to the meeting room: 2202. You'll need to get to the heavily guarded elevator to get to the delegates though. Utilize either your stealth skills, or gun your way through them, it's up to you how you do this.