Two slips, a leg slip and a short leg assumed their positions as Craig zeroed on the footmarks outside off stump.
McCullum would chat to Craig, move his fielders around and make sure the batsman was within earshot.
With England four down, McCullum even inserted himself at silly point when Stokes, the man who blasted the 85-ball fastest century at Lord's, entered.
The captain was unflinching, even when Craig dropped short and the all-rounder's backlift took a deep breath, tipping beyond the horizontal in prospect at drilling the ball through McCullum's solar plexus.
At lunch England were 102 for five with rain scheduled to enter down the order in the early afternoon. The precipitation instead proved an unreliable teammate who skirted the ground and failed to prevent New Zealand levelling the series.
New Zealand completed their second test win at Headingley, fifth in England across 54 tests, ninth in 101 tests overall and extended their run of undefeated series to seven. Extraordinarily, their ranking will drop from third to fourth regardless.
3. A day for tweak
Mark Craig continued a fine test after struggling with the ball at Lord's. He supplemented two for 48 from 26 overs in the first innings with three for 73 from 31.5 overs in the second. Those figures included 15 consecutive overs and seven maidens from the Kirkstall Lane end in the opening session, as his responsibility grew.
The decision to open with Craig was sound. McCullum looked for him to hit the footmarks outside off stump against England's seven left-handers, and especially Alastair Cook, who appeared to have a GPS locator on his off stump to pace bowling across the last three innings.
Williamson was also outstanding, taking three for 15 from seven overs. He might be a part-timer but he took specialist wickets: Cook for 56, Ben Stokes for 29 and Stuart Broad for 23.