Reaching the research facility | Laboratory Walkthrough Resident Evil Zero HD Guide

After defeating the boss, the next step is not so obvious. A part of the roof was destroyed when the bat entered the church (the game will point to it when you approach the door). Use Hookshot to make it to the ceiling.

Leave the church (M4,1). Now, with at least one of your characters, you have to go back to the area with the train wreck. Head to the door leading back to the Observatory (M2,35). Go through the Observatory and take the door leading to the balconies outside the building (M2,17). Before, there were zombies here. Now you will meet some monkeys. It is good to eliminate all of them, because you will be going back here. When the fight is over, use the passage to the conference room (M2,5). Reach the ground floor of the main hall (M2,5). Find the hatch shown in the screen above and use the ladder.

You will find the Hookshot near the train wreck.

After using the ladder, you will find yourself in the sewers (M2,2). Go through them again and reach the tunnel with the train wreck (M2,1). Look for the Hookshot. Add this item to the inventory of any of your heroes and head back the same way, to the church (M4,1).

Enter the church (M4,2) with the hero that has the Hookshot in their inventory. Stand below the destroyed fragment of the roof (like in the screenshot above), open the inventory and select Use on the Hookshot. If you've done everything correctly, you will find yourself on the roof (M4,4). Go across the roof to a place where you can see a ladder and use it to go down.

Now you are at the back of the church (M4,5). Interact with the switch on the wall, which will activate the elevator. Head to a nearby door and unlock them from this side. Now you can summon your partner and use the elevator (M4,6).