Reach the start of the chapter Hillcrest through Chapter Select or natural progression.
Enable Traversal Audio Cues, Navigation Assistance, and Enhanced Listen Mode (set to 30m).
After finishing the theater portion Ellie will wonder if she found Hillcrest before hearing gunfire in the distance. When you regain control:
1. Turn around. To do a 180 degree turn, press back on the movement stick and the jump button.
2. Fall down into the sinkhole.
3. Use Navigation Assistance and Enhanced Listen Mode to guide you to the Trading Card.