When running towards the raised ground, jump onto it and your legs will clip through it, keeping contact with the common ground. When walking forward, you will sometimes clip into the building itself.

It is possible to escape from captivity: when you're inside of the building, walking/running towards the interior wall (which is texture-less, transparent) and jumping will occasionally clip you out of the building.

A .zip-file is attached with three in-game screen-shots. The name describes the image.