The Last of Us Walkthrough: The Firefly Lab / Jacksonville: 4 Artifacts, 1 Firefly Pendants and 1 Comic
After Joel runs to the operating room next floor and right after blocked the door with the chair, you will find the next artifact on the table.
Artifact 2: Marlene's Voice Recording
Walk straight and then move to the right. Before turning, you will find a door on the right.
Artifact 3: Marlene's Journal
Marlene's Journal can be found in the firefly tent area on the second floor. This area appears towards the end of the chapter.
Artifact 4: Marlene's Voice Recording 2
The second voice recording can be found in a room with full of boxes. It lies in direct proximity to the boxes.
Firefly Pendant 1: Bryony Stewart-Seume
After you collecting the voice recording, you climb over some tables and the window to your left needs to be broken. There you will find the next pendent.
The Last of Us: Jacksonville: 1 Comic
Comic 1: Singularity
The only comic you will find in this section, you walk with Ellie on the left side of the map to view the wrecked car. There you will find the comic.