Mandukya Karika, verse 4.34


न युक्तं दर्शनं गत्वा कालस्यानियमाद्गतौ ।
प्रतिबुद्धश्च वै सर्वस्तस्मिन्देशे न विद्यते ॥ ३४ ॥

na yuktaṃ darśanaṃ gatvā kālasyāniyamādgatau |
pratibuddhaśca vai sarvastasmindeśe na vidyate || 34 ||

34. It is not possible for a dreamer to go out in order to experience the (dream) objects on account of the discrepancy of the time involved in such journey. Again, on being awake, the dreamer does not find himself in the place (where he dreamed himself to be).

Shankara Bhashya (commentary)

The time and space involved in undertaking a journey and in coming back, have a definite and fixed standard in the waking state. These are seen to be reversed1 in dream. On account of this inconsistency it can be positively said that the dreamer does not actually go out to another place during his dream experiences.