×Get the wubba diagonally aligned with the trapdoors, and use the keg to block it. Walk to where the eye is - this will make the wubba move towards the main timeline Beethro later. Now push the keg while the wubba is still there.

Now push the wubba. In the final timeline, you'll push the keg instead.

Bear in mind that the wubba will end up on the corner square, so don't make moves that depend on that square being free. Also, remember that the green doors will be open in the final timeline.