Stopping Marchenko

M16: Stopping Marchenko is the 16th main mission in Deus Ex: Mankind Divided, and one of the last missions (depending if you did M17: Protecting the Future) first. Adam Jensen must stop Marchenko from detonating bombs that will kill hundreds of people, but at the cost of the UN delegates lives and letting the Human Restoration Act pass.

Achievements

 * He's [Not] Dead, Jim
 * Laputan Machine
 * Spokes in Two Wheels

Starting the Mission
This mission initiates after completing M15: Securing the Convention Centre by meeting Jim Miller in the catering area. If you did M12: The Heist and got the Orchid antidote, you can use it to save Jim Miller or, if you do not think you will make it to the delegates in time, save it for them. Alternatively, this mission will also initiate if you triggered an alarm in the convention hall. In this case, you can still find Miller in the catering area to save him using the Orchid antidote, but only if you do so before fighting Marchenko.

If you met with Miller, you are given a choice of either confronting Marchenko or instead proceed with M17: Protecting the Future to save the delegates. You may proceed either way.

Stop Marchenko Before He Blows Up the Towers
The following special items may be used during the mission Contrary to what Marchenko says, he will not immediately blow up the towers. The timing constraints are summarized below. Using the killswitch is the easiest way to defeat Marchekno. However, if you do not have the killswitch or chose not to use it, you will then fight Marchenko.
 * Signal Jammer – If you did M11: Confronting the Bomb-Maker and got Allison Staněk to give you the Signal Jammer, you can potentially use the item to prevent Marchenko from detonating the bombs.
 * Marchenko's Kill Switch (Damocles' Sword) – This item can be found in one of the rooms in the catering hallway. You can use it during a cutscene prompt when entering the exhibition hall, or anytime during the fight with him. Please note that using the killswitch voids the Pacifist achievement.
 * If you have not yet completed M17: Protecting the Future, there is no time constraint. The timer for Machenko's detonation of the bombs does not start until M17: Protecting the Future is completed.
 * If you have completed M17: Protecting the Future (i.e., you have already reached the VIP room with the delegates) and have not yet entered the exhibition hall, then you normally have 10 minutes to get from the VIP room to the exhibition hall.
 * If you have neither the Signal Jammer nor the killswitch, then you cannot prevent Marchenko from detonating the bombs if the 10 minute period has elapsed.
 * If you have either the Signal Jammer or the killswitch, then you have an additional period of time to get to the exhibition hall.
 * After the elapse of this additional period of time, Marchenko will detonate the bombs regardless of whether you have the Signal Jammer or not.

An easy way to defeat Marchenko is to use an electric shock to stun him (such as the stun gun) and quickly proceed with a takedown. If using the stun gun, make sure you are in stealth, otherwise Marchenko will activate his TITAN aug, preventing the shock. Another method is to make a couple EMP mines and lure him in. When they go off, you can then run over and do a non-lethal takedown.

If you've defeated Marchenko but have not yet saved the delegates, there is a shortcut from the exhibition hall to the room with delegates. From the main entrance area of the exhibition hall, make your way up the stairs to where the turret is to find a switch underneath the table (near the mines) that will open a back entrance to the delegates. Follow the arrows to the executive lounge and enter. This path allows you to reach the delegates within a very short amount of time, making it easy to save the delegates. This path may also be used to exit the exhibition hall during the Marchenko fight.

Alternative Objective: Defeat Marchenko
If Marchenko detonated the bombs, then the objective simply becomes defeating Marchenko. Defeat Marchenko to complete the mission and proceed to the ending.

Aftermath
If you complete this mission last, Jensen tells MacReady that "it's over," and steps toward the window of the exhibition hall. The game will then cut to the ending and you can see how your choices play out in your conversation with Alex and on the news.