Walk
Walking represents living, and usually means living according to the true things taught to us by the Lord -- to "walk in His ways." When the Lord is pictured walking, it means life itself.
Enter
All changes of place in the Bible represent changes in spiritual state. “Entering” – usually used as entering someone’s house or “going in unto” someone – particularly means adopting a spiritual state that is compatible with someone else in order to communicate with them or be conjoined with them. This is easily seen in the fact that a man “going in unto” a woman is sort of a Biblical euphemism for a physical relationship. In a broader sense, all the spiritual changes we go through in our lives involve “entering” and “leaving,” so when the Bible uses the phrasing “going in and coming out,” it symbolizes someone’s entire spiritual life.
To enter, as in Genesis 7:1, signifies to be prepared.