This traverses the dark walkway cave underneath the BNI boulder, emerging to finish up Sabotage. Start crouching at the left end of the roof, LH on protruding sidepull, RH on low slot on left arete. Gain the next slots and launch into a very technical and contorted crux. Pull out onto the hanging slab at the start of Sabotage (shake out). Finish up Sabotage and BNI. Font 8a + Font 8a = 30 hard moves and hardest at Dumbarton.