He was promoted to captain on 10 December 2006, followed by promotion to major on 10 December 2010. He attended the Defence Services Staff College at Wellington. During his service, he was attached to the Rashtriya Rifles in Jammu and Kashmir, and also served with the UN peacekeeping force in the Democratic Republic of the Congo (DRC) during the ongoing Kivu conflict. Colleagues who served with him described him as "empathetic, yet bold." During a major joint operation conducted by DRC and South African forces against Nduma Defense of Congo (NDC) rebels, Babu and his unit were caught in cross-fire, yet his bold actions prevented the rebels from inflicting casualties on the joint force. During his posting in the Congo, Babu was described as kind and generous towards local residents, assisting them with medical and other needs.