This is a forensic breakdown of what was actually happening in the Cape Town scrums, going well beyond the Rennie-Erasmus post-match briefing war. The piece examines both coaches' legal arguments on the merits: Rennie's 'walking around' charge is reconstructed as a specific shear technique — South Africa sets fractionally left, isolates the New Zealand tighthead from his support, then drives through him straight — and the piece concedes the manoeuvre is real and illegal when deliberate. But Erasmus's counter-argument gets its due too: if a tighthead initiates the angle change and a loosehead follows it, the man who followed can end up looking responsible for a movement he never started, particularly from the referee's vantage point. Nché's hip mobility is the key variable — his rotational range lets him track an angle a tighthead sets while maintaining his spine line and hooker connection, meaning the geometry shifts without him visibly doing anything wrong. That's why Steenekamp, with longer levers and none of Nché's rotational capacity, gets penalised where Nché doesn't. The piece also unpacks Erasmus's deliberate use of Nché as a 35th-minute impact substitution — after letting Lomax groove a comfortable body height against a same-sized Steenekamp for two thirds of the first half — as the calculated tactical move it was. A third factor neither coach touched: DHL Stadium's surface, where a late afternoon Atlantic dew on a firm root zone creates exactly the worst-case conditions for set-piece stability, and may explain much of the collapse volume without any illegality on either side. The conclusion is that Rennie had the better mechanical argument and Gardner refereed accordingly — policing setup and hooker spacing rather than the hit itself — but one penalty against six doesn't indicate a dominant illegal pattern, and Erasmus got the outcomes that mattered. The piece closes with what changes in Soweto: firm Highveld turf, Amashukeli on the whistle, and if Nché starts, Lomax gets the low-man problem from minute one rather than having it sprung on him mid-half.