At dawn on 27 March the forces departed, hampered by a thunderstorm and Zulu sniping by the light of lightning flashes. Buller's mounted troops reached the summit by the following day and African infantry began herding cattle westwards. As Russell's troops occupied the lower plateau, Wood encountered a group of the Border Horse who had become detached from Buller's advance up the higher plateau. Wood ordered them to advance towards the firing on the upper plateau but the men, mostly English settlers from Transvaal, refused. Wood rode on with his small party, intending to follow Buller's track up to the summit and was eventually followed by the Border Horse. Coming under fire from caves, as had Buller's men, Wood was again defied by the Border Horse when he ordered them to clear the way forward. Five of Wood's escorts charged the caves; Wood's staff officer Captain R. Campbell and his political agent, Mr. Lloyd, were killed. The group moved westwards to join Russell on the lower plateau.