This scenario is triggered as you explore the Amusement Park area. This scenario will also be completed after encountering Christophorus in the circus tent. After the scenes, the scenario will be complete. Before moving forth, there are several cat demons and a bomb that will appear from your starting location. Defeat them then continue forth. You can examine the event items that were featured in the cutscene earlier if you want.
Follow the path until you see some flaming floor traps. There are two chests behind it, including one chest that gives 400 bonus blood. Continue along the path then go to the NE to check out the dead-end area there. There's a pile of crates that you need to destroy. Enter the area and defeat the enemies to reveal a chest containing 400 bonus blood.
Backtrack to the main path and continue to the west to find another stage surrounded by flaming floor traps. Defeat the group of enemies that will spawn to remove the barrier and for you to continue to the next area.