Forget what one is leaving behind and focus all attention on the task at hand

When being dropped off on his attempt to reach north pole on foot.

"I was now fully aware that from here on, I would be totally alone in the face of my challenge. Until now, I had been helped, surrounded, financed, supported, and conveyed by people who believed in me. But once that helicopter lifted off and carried away the last of those people, it would be up to me to play this game -- me and me alone."..."Nobody said another word. The emotions were beyond words. Everyone knew that what I was about to try to do would define the next stage of my life."..."Everyone climbed back into the helicopter, which quickly took off. I turned my back on the aircraft as it labored into the air, to face what awaited me. For the moment, what I most needed to do was to forget what I was leaving behind and focus all my attention on the task at hand."

- Mike Horn in 'Conquering the Impossible"