I chose to update the description so people can know to do your solution.

If you're meant to use the faith plate to return from the conversion gel area, it's impossible. There's a 1000 UPS speed cap when the player goes through a portal, so even though the plate gives you 3000 the player doesn't travel up to the main area. Try lowering the ceiling/raising the floor a bit and it should work fine.
You can also avoid doing the conversion gel test by portaling down, pushing the button, then using the portals that got you to the lower area to return to the main area. Maybe have the button flip the panel that the player used to get to the bottom so that their portal is removed.