The sealing of a boundary of a sacred space, e.g., casting a circle, putting in protective stakes in the four cardinal directions, drawing a pentagram, and so on, is for sealing-in and for keeping-out. Nothing comes in and nothing goes out (until the seal is released). The event horizon of the historical-temporal Singularity is also a boundary, a boundary of information, but it is unidirectional; everything is attracted into it, but there is no information forthcoming beyond the threshold.
As the Great Attractor unto concrescence, inasmuch as it takes the totalized everything of history into itself, it absolutely needs no protection from anything. Concrescence is the superposition of all polar states, of the empty set and transfinite Alephs, of nonbeing and being, of dispersion and gathering, of the instantaneous Now and eternity. It is history itself that is being protected from concresence, even as it is unprecedented Novelty. History accelerates faster and faster toward it, inevitably toward ultimate synchronicity.