Stage Four (3?): Instead of using any of the underground passages you could have the last level as the survivors being directed towards some indicated point in the forest where it is assumed that there is a supply shed filled with fuel they can take back to Virgil. However it seems like the group is stuck in the study with no particular way out until one of them triggers something at the end of the previous stage. What this might be or how it might occur is something for debate but it seems like the most efficient method to get the survivors where they are going without running forever through the forest. When they leave they find themselves in the second mansion where they will have to search through the mansion for the gold after triggering a panic event or perhaps some other device like a invulnerable tank that, while having 1 hp, cannot be killed until the survivors follow the clues or the signs to the gold room/area within the mansion. Think of it akin to that Resident Evil creature that followed you through the game and appeared when you were going too slow. Witches would be rampant in this area making for a mine of danger if anyone just tries to careless open doors left and right. If it were possible for the location of the golden gateway to be randomized that would be best but for now it could be treated as the safe room where the survivors would hit the next stage for the finale event after seeing what looks like something glowing golden in the next room, or perhaps another glimpse of butterflies.
1:00 - Vaguely BURNING WITH A PASSION: Stage Five (4?): The survivors find themselves in the second safe room again, the mansion afire and the gardens torn through. The messages on the wall are different, in new handwriting and likely in blood or perhaps in glowing handwriting saying things to the effect that the survivors were going to be apart of the ritual and no man of Dante's (A reference to Virgil) would be able to save them. The beginning is quiet as they leave but soon enough the screams of the horde begin as boiler room in the mansion blows, triggered by the survivor's entering the beach area. They then must fend off the horde. If its possible you might hear a rifle and see an occassional shot into the horde from the burning mansion or the chapel signifying someone still alive back there as a bonus if thats possible. Much like the original survivors helping during the end of The Passing, but to a much much lesser degree. The survivors are then taken away once Virgil arrives after a specified time limit. Alternate ending might be the survivors being on the boat only to have a final shot of them standing on the pier as it was during the opening, with Virgil telling them they need to go and check for survivors and fuel up at that big house on the hill.