This is the Danakil Depression in Ethiopia, lying within a colossal rent in the Earth's surface where giant land masses are pulling away from one another.
This brings Paul inner turmoil as he doesn't want to be capable of these unspeakable acts — but Jessica continues to push him, all while he starts pulling away from her influence.
Isolation creeps in when your new boyfriend or girlfriend starts pulling you away from your friends and family, your support system, and tethering you more tightly to them.