"Yet he has shallow roots and only lasts for a little while." The root represents what makes a person continue to believe God's message. Alternate translation: "But like a plant that does not grow deep roots, he only endures for a little while" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here "falls away" means stops believing. Alternate translation: "immediately he falls away" or "he quickly stops believing the message" (See: [[rc://en/ta/man/translate/figs-metaphor]])