In chapter 12 of WoR, Kaladin infuses the chasm wall with stormlight, then picks Lopen up and sticks him against the wall. The context clearly states that he is stuck to the wall by the back of his shirt. Now, unless we can assume that shirts have no holes of any size, microscopic or massive, no holes at the seams, etc, the shirt must, effectively, be glued to the wall. No vacuum could exist if the shirt had holes, which it must. Also, for the same reasons, it would be impossible for pressure to push it against the wall. Thus, the back of the shirt must be gravitationally stuck to the wall. It is not a pressure surge binding. Unless, of course, we are talking about an entirely different pressure surge than what it actually is, aka basically super powerful magnetism between not necessarily magnetic materials.