As you make your way down from the meeting with Brecken and Jade you learn that Bahir is acting strange and has locked himself in his room. The others are trying to get the door open with no success.
You are asked to try - to get in you need to pick the lock (easy) - but when you get inside you find Bahir on the floor complaining that he cannot move - he is not turning but he tells you that the Antizin he took did not work.
You examine the drugs and realize it is not genuine - you convince him to reveal who sold him the bad drugs - then you head off to get Dr. Lena.
After you show the vial to Dr. Lena she asks you to talk to Yusuf - who you learned was on the roof. You head up there and find him keeping store there.
When you ask him for Antizin he admits that he has some - and then you confront him. He denies it and then tells you he acted in good faith. Now you have to convince him to tell you the truth. He does - and then you give him the ultimatum - burn the bad drugs or else.
Your next task is to check the drug store...
As you head outside of the Safe Zone be sure to pay attention to the time - now may not be the ideal time to go out on a mission but you could do some scrounging... Just saying.
If you have the time though the Drug Store is not the far from the Tower. As you get outside you hear from Lena - who has found two more vials of fake Antizen.
When you get to the Store you discover that Yusuf has already been there and ratted you out - a battle then ensues - and you have to deal with ALL of the Bandits there!
After you take out the Bandits you can strip the lab of resources and then you report to Lena and she confirms that Yusuf did indeed slip away earlier.