A video has emerged showing the crew of the sunken Indonesia submarine singing a ballad together on board the vessel. Submarine commander Lieutenant Colonel Heri Oktavian was among those gathered around one of the seamen strumming the acoustic guitar. Oktavian did the MSc (Strategic Studies) Programme at RSIS over the 2014/2015 academic year. The RSIS Alumni Association paid tribute to the fallen leader in a Facebook post on 26 April.