Hunting Dr. Samuel Billingsley
New objective: Go to the Blacknet terminal
In order to start this mission, you have to get to location [237, 1172], specifically to Blacknet terminal.
New objective: Use the Blacknet terminal
The terminal can be used only by soldiers, scientists and Blackwatch employees, but fortunately you do not have to look far. Decide to grab and consume (B button and Y button) one of the soldiers standing near (screen above). If possible, try not to trigger an alarm, because you would have to unnecessarily spend time on elimination of enemy units. You can now approach the terminal and use it (B button).
New objective: Hunt and consume dr. Samuel Billingsley
As you probably remember from the last mission, it is best to start the hunt with getting to the rooftop of one of the highest buildings in the area. Only then send an impulse (press left analog stick), so you'll easily find the location of the commander you're looking for (screen above).
An exact location of Dr. Samuel Billingsley is in [362, 1234]. I suggest approaching the scientist disguised as a soldier, so you won't alarm any opponents in the area. Consume Billingsley (B button and Y button) in order to obtain his shape and memories.
Getting to the Gentek facility
New objective: Go to the Gentek facility to find Rooks's location
New objective: Equip a military form to safely enter the restricted area
Your next target is in location [135, 1322]. Once you get there, watch short movie, from which you'll learn about functioning of fenced areas and that to get inside you need to consume one of the Blackwatch soldiers to obtain his shape. So approach the guard patrolling the area and consume him (B button and Y button). Notice - if you've consumed any soldier before getting to the facility, you can skip this step.
New objective: Use the hand scanner to enter the restricted area without arousing attention
This is very simple task. Go to the main facility entrance gate area in location [135, 1318] and interact with hand scanner (button B).
New objective: Consume the commander to enter the facility
The commander resides in location [95, 1319], so you do not have to look for him. Approach the person indicated by the game (screen above) and consume him (button B and button Y).
New objective: Use the hand scanner to enter the facility without causing an alert
Also this target is not too complicated. The entrance to the building can be found in location [118, 1336] and you have to interact with the hand scanner (button B).
Getting to the Gentek lab
New objective: Stealth consume the commander
Go to the adjacent room in location [122, 1305]. Learn about consuming people who are observed by someone. In this case the commander is in the line of sight of soldiers standing on the right. You can check it by sending an impulse, because all observed characters are indicated in red (except white). Additionally you can target the commander after sending the impulse (left trigger), so he will be marked with eye icon above him.
A solution to this problem is fortunately very easy. Get the soldier behind and consume him (B button and Y button). Only after that action decide to consume the commander, who is not observed by anyone right now.
New objective: Use the hand scanner to enter the lab without causing an alert
Return to previous room and head to the hand scanner, located on the floor in location [91, 1371]. Interact with it (button B).
Using the terminal in the lab
New objective: Stealth consume Dr. Genovese
Same as in case of the previous commander, first you have to check, by whom Dr. Genovese is observed (location [117, 1351]). So send an impulse while pressing left trigger, thus learning that he is in line of sight of two soldiers (screen above).
Go to each soldier and consume him (B button and Y button). Only after eliminating soldiers, go to Dr. Genovese and consume him.
New objective: Use the terminal without raising an alert
This is very easy task. Go to the shiny circle (screen above) to interact with terminal and watch a new cut-scene.
New objective: Exit the Gentek facility
Return to the main room, descend to lower level and find a hand scanner (screen above) in location [150, 1325], so you can go back to the surface.
Do not go to the main gate but at any place use sprint option (right trigger) or perform a long jump (hold A button) in order to get past the high wall (it should be enough to start the alarm). Move away from the explored facility to end the mission. Notice, that as a reward for completing the mission you can choose a mutation from Offensive category. Additionally the game will unlock a new main mission - Brain Drain.