The mur seems to be protecting itself from the horizontally spinning mech-men of the sphère . They offered their exposed necks to Jacob , a signe of self-sacrificing yet murderous intent, part of their telepathic culture. Lacking proper throats and lungs, it is the only way they find polite to talk in threatening tones.
De derrière le bouclier, j'attaquerais avec la marque de Caïn.