The next room is a macabre chapel, complete with mummified bodies filling the pews and kneeling in prayer. Along the sides of the room are 2 wheeled carts with rotating mirrors and 6 dioramas, in which various stations are dramatized by corpses.
If you mess around a bit, Lara and Jonah will provide a clue in the form of the pamphlet Jonah gave Lara earlier, "Seven Steps Closer to God." This can be found in the Artifacts menu under Miracle Mission. You're looking for the sixth station: Jesus is crucified.
The diorama depicting this is the one in the far right (west) corner, "Jesus, nailed to the cross." But there's no way to shine the light on it directly.
Start by pushing the left cart forward...
...until the light shines through its lens.
Now rotate the lens so the light points toward the middle diorama on the left (southeast) wall, showing Jesus being lifted onto the cross. This causes the handle to pop out of the wall below the diorama.
Push the handle to reveal a mirror...
...which then reflects the beam of light toward the other side of the room.
Pull the cart on the right toward the entrance until the reflected beam strikes its lens.
Then rotate the lens so the light shines on the left diorama, depicting the crucifixion.
This extends the handle below it. Push the handle to open the exit and trigger a cutscene.
Lara and Jonah enter the inner sanctum, an eerie depiction of the seventh station, "Jesus is entombed." The megalomaniac Lopez got at least one thing right, it would take centuries for anyone to discover the location of the Silver Box, but here it is.