An island is someone who is not accessible to other people. A swamp is someone who, having established a meaningful relationship with others, tries to suck them in so deep that they cannot see any daylight outside the relationship.
In a way, this goal says don't drop out from the human race or make the mistake of thinking that the center of the human race coincides with your own navel. But it goes beyond that. If you are not an island, you will feel others' pain and consequently help them when you can. If you are not a swamp, you will not expect them to be eternally grateful for that help.