Here’s the good doctor’s lab notes for episode 1.10 “Safe”. Walter reflects on some of the science behind the ‘phasing’ seen in the episode. He posits that, in principle, subatomic vibrations can allow particles to phase through ‘solid’ objects. He also rambles on a bit about his hiding places and “stolen details”. He appears to be talking to the “Alter-Walter” who paid him a visit in “The Equation”.
The lab notes are accompanied by a picture of poor ‘stuck in the wall’ Raul, and his decapatated hand.