You cannot overcome your animal nature. You can’t learn to totally stop breathing, because that wouldn’t do your body any good.
Look at things already in line with your animal nature and exploit those. For instance, “out of sight, out of mind.” When you’re already running, it’s easy to take another step. It’s the first steps to get outside the door that are tough.
The moment of uncertainty, the ability to choose to go back, actually makes it harder.
I went skydiving recently. The scariest moment was holding onto the doorway of the plane, looking 14,000 feet down, asking myself if I was really about to jump out of a perfectly good airplane. The falling was easy, moving past the door was not.
Imaginative creatures automatically think as far into the future as possible. We imagine what passing through the doorway will bring, and sometimes it stops us from moving. But often the imagination is wrong. Sometimes, don’t think, just focus on what you can do. Working gives momentum.