I think it's a reference to "getting the wall" aka summary execution aka one of the great crimes against humanity perpetrated by revolutionaries in the past that is cause for understandable distrust among leftist non-communists especially, anarchists like myself, whose philosophical comrades were among the murdered.
OP, please don't go there. We're better than that and don't have to repeat the tragedies of the past.
EDIT: To try to reduce the friendly fire, I did not recognize that this image was from the Romanovs.