The third level represet innate desire in each of us, to escape from the mediocrities of present into something better--a time-travel into a time of possibilities and freedom-please make me understand the meaning of this line?

 

Yes, the third level was a medium of escape for Charley from the unhappy modern world that is full of insecurity, fear, war, worry and the like. This is because he could never find it again at the Grand Central Station.

Charley did not agree with his psychiatrist friend when the latter called his experience of visiting the third level ‘a waking-dream wish fulfillment.’ His friend tried in vain to make him realise that his hallucinations are a result of his strong desire to escape to the peaceful times of the 1890s.