Answer:
In we go, out we go. All around and in a row. Always, always steady flow. When we'll stop, you'll never known. In we go, out we go.
It can cause deflation of tires when dropped from the rear of spy cars.
Though blind as well, can lead the blind well.
A building where people and stories are on stage
What word starts with 'E', ends with 'E', but only has one letter? It is not the letter 'E'.
What covers its face with its hands, speaks no language, yet most known what it's saying?