I'm pretty sure it's a trap, anyway, perhaps me and my girlfriend just didn't see an escape.
So we were exploring the Great Siphoner Pools and noticed an agility jump of 7. We came back later with a supersoldier drug we got off one of the fellas at the Aegis camp, which boosted our agility from 5 -> 7. We jumped over, looted the rare ingredient plus a green wort and checked out the crevice at the back which gave us a chuckle. By this point, the drug had worn off. So we were back to 5 agility and could not jump back. As I said, we couldn't see an escape, nothing along the waterline besides the agility obstacle (and there's little point of the obstacle in this place if they were going to just let you walk past anyway), there didn't seem to be anything along the rockface. Just as well we loaded an auto-save.
Version 1.1.0.12