The psalmist does not really want to flee. He is posing ideas and questions so that we can see that wherever we are, we are always under God's scrutiny. God is a positive spirit. Everything that He creates has positive function and beauty. His intention in everything for us is always positive, right, and good. He does everything in love and concern for our well-being so that we will fit within His purpose, and it will be worked out in our lives. Psalms 139 contains no negative connotations.
From this, because His mind permeates the entirety of His creation, we ought to derive great confidence that God is always with us. He is omnipotent. He is omnipresent. He is actively using His powers, His Spirit, to govern and manage His creation.
The beginning of the source of all power is in the mind. Remember, man is in God's image. A man may make tools to intensify his powers, but the real power is in the mind because without it, he would not be able to create the tool that expands his powers.
God's Holy Spirit is the essence of His mind. Just like a man, His power resides there too, only He does not have to use steam shovels and power tools to get things done. He speaks, and the laws He has created go to work. The tool by which He carries everything out is His Spirit, the essence of His mind.