A low circular wooden walkway. A large canvas sack hanging from the ceiling. One sickening second to realise someone may be inside that sack, before it plummets to the ground. This is how Patricia Cornelius’s new play, RUNT, directed by long-term collaborator Susie Dee and starring another long-term associate, Nicci Wilks, opens: a thudding coup de théâtre that immediately establishes the work as incitement, as agitprop, as uncompromising sucker punch.