If you block the path of walking kleiners, they try to walk around but eventually give up and get stuck, saying in one spot for eternity. Same happens if they bump into each other, the issue can reach critical mass where all walking kleiners are just standing in one spot, clumped together. They are also always walking into the glass, turning around and going towards the front door. If the glass is broken, they still come back towards the front door in a ritual like movement.