Look for Dina and Jesse
Once you're up and running, head back towards the the main room of the theatre, but before going through the red curtain, look to your left to find a Trading Card 41/48 sitting a piece of equipment.
After the cutscene, follow Jesse until you reach the WDL building, then continue onwards to find an open door with a cabinet blocking the way. Crawl under to find a Workbench and a Trading Card 42/48, then press onwards to the next area.
Quickly take out the enemies by crawling through the grass, then head into the building on the right to find some Supplements. Follow the path ahead and climb through the window via the van in the building on the left, and then continue along until you find an area where you'll have to swim again.
Explore the Garage
Here you'll want to head into the garage on the left and take out the enemies, then go to the back of the area to find an Artefact 72/117. Exit the garage and drop back into the water, then climb up to the area on the right and head into the building via Jesse's assistance.
Drop down to the gate to find a Trading Card 43/48 underneath the broken path, then go over to the children's area to find an Artefact 73/117 on the table. Leave this building and take out another group of enemies up ahead, then go up to the 2F of the building on the right to find another Artefact 74/117.
Dive into the water on the right and walk up the muddy slope on the left. then climb up and walk left to find some Scrap and a Workbench. Now crawl through the gap and jump over the wall to view a short scene. Finally, follow Jesse into the building and drop down, here you'll find a Trading Card 44/48 inside the table you have to jump over, then move the pipes to get through.
Tip: There are no more collectibles to find in this next area, but make sure to explore it anyway, as you can find ammo and resources.
After the cutscene make your way over to the recently parked boat by using the corridors as cover, then once you've made it onto the boat, use [L1] to move and escape.