[ ] Green Herb - On a shelf in the back of the room.

First up, head back the way Parker came when he was with Raymond. You'll want to enter the Locker Room, which is to the north. Once you're in there, just step back out into the hallway on the other side. Parker and Jessica will chat a bit as you move, so just let them talk.

Now, you'll be in Office Hallway 1. Parker needs to hop over that blockade in the north corridor. Follow this corridor all the way to the door at the end, and open it up to enter the Stairway area.

Your goal here is to reach the fourth floor. Parker's on the third floor right now, so you just need to go up one level. As you start climbing the first set of stairs, get ready! A Hunter is going to attack, so quickly switch to your handgun and take it down.

Keep moving up to the very top of the stairs. You'll find an extra herb pickup here – that's the one we're after! Just so you know, if you happen to pass the fourth-floor door and keep going up, Jessica will call your attention to it. If you decide to push further up the stairs after reaching the fourth floor, another Hunter will attack. The doors to the other floors are locked, so don't worry about those.

Finally, open the door to the fourth floor and step into the hallway. You've found the Green Herb!