The Confrontation was a strange, shadow conflict. From 1962 to 1966, Indonesia sought to prevent the creation of Malaysia by launching cross-border raids into the British-protected territories of Sarawak and North Borneo. It was never declared a war, and most of its engagements were small: platoon-sized patrols clashing in jungle so thick that combatants sometimes passed within meters of each other without knowing it. The British responded with their own covert cross-border operations under the codename Operation Claret, sending elite infantry deep into Indonesian Kalimantan to attack camps and disrupt supply lines. By late 1965, the 2nd Battalion of the 10th Princess Mary's Own Gurkha Rifles had taken over responsibility for a sector south of Bau, tasked with eliminating a series of Indonesian camps along the Sungei Koemba river.

On the morning of 21 November, C Company under Captain Christopher Maunsell set out to locate and destroy J Parachute Infantry Battalion, which was establishing a base near the village of Serikin. A reconnaissance patrol discovered two Indonesian positions: a platoon dug in on the summit of a steep, jungle-covered hill, and a company-sized force on a lower spur about 500 yards to the west. The terrain dictated the plan. Maunsell would have to silence the hilltop platoon first, using surprise, before the larger force could react. A support position was established 800 yards out with an artillery forward observer, and a separate platoon was placed to pin the company position with covering fire. By noon, preparations were complete. Maunsell led two assault platoons in single file up the ridge, with Limbu's sixteen-man advance party crawling ahead to clear the way.

When the sentry opened fire and the element of surprise vanished, the battle became a close-quarters fight up a jungle hillside. Limbu destroyed the first machine gun with a grenade, then exposed himself to enemy fire to report the situation to his platoon commander before returning to press the assault. On the main axis, 8 Platoon under Lieutenant Ranjit Rai suppressed another machine gun and cleared a hut inside the Indonesian perimeter, though one Gurkha was killed and another wounded in the process. On the left flank, 9 Platoon's advance stalled under fire from a second machine gun pit. Limbu charged again, silencing it with another grenade while a two-man Bren gun crew provided cover. The three men jumped over the wrecked position, but one Indonesian survived long enough to fire a burst that hit both members of the Bren crew before being killed himself. What Limbu did next defined the action. Over twenty minutes of near-continuous enemy fire, he carried both wounded men, one at a time, to the shelter of the cleared hut. Both died of their wounds shortly afterward. Limbu retrieved their Bren gun and provided covering fire through the final stages of the assault, killing four more Indonesian soldiers as they tried to flee across the border.

After more than an hour of fighting, the Gurkhas had cleared the hilltop. But the company-sized force on the lower spur began pouring fire onto their position, and Maunsell recognized the danger of remaining. He ordered a withdrawal, covered by accurate howitzer and mortar fire directed by Lieutenant Douglas Fox. C Company was successfully extracted along the ridge. The medical officer, Captain Jack Wynters, met the column on the trail, treating the wounded and walking beside them through pitch darkness back to Serikin, one hand holding an intravenous drip for a casualty. The Indonesians had suffered at least 24 dead, with unknown additional wounded. The British lost three killed and two wounded.

For his actions at Gunong Tepoi, Rambahadur Limbu was awarded the Victoria Cross, Britain's highest military decoration. Captain Maunsell, Lieutenant Rai, and Lieutenant Fox each received the Military Cross. Limbu went on to serve with distinction, eventually becoming an honorary officer and settling in the United Kingdom. The battle itself was one of many small, fierce engagements along the Borneo border that never made international headlines but collectively broke Indonesia's will to continue the Confrontation. A peace treaty was signed in August 1966, and President Sukarno was removed from power the following year. The jungle around Bau has long since reclaimed the ridgeline where the fighting took place, but the Victoria Cross citation preserves, in its terse official language, a record of what sixteen men did on a hillside they had to crawl up on their bellies.