Question

How was the third level different from other two levels

Answer 1

The third level indicated time travel. Charlie when entered the third level found himself in the early 1894. The other two level above it are normal subway metro stations of the present.

Answer 2

Answer:

The story refers to the discovery of a third level that is very different from the routine and hardcore life. In any case there is a structural difference between the third level and the other two levels, and this story takes place somewhere in 1894.

The third level of Grand Central Railways station gives an idea to the man who  wanted to get away from the miseries of life.