 On July 29, 1966, a second coup d'état took place after a majority of the Nigerian Army led by 32 army officers rose up against Ironsi's dictatorship and assassinated him along with several other Igbo officers and politicians.Kalu hosted an early afternoon meeting at his house in Kaduna where he informed several south-eastern officers about the coup and that their lives were in danger, these officers included Lt. Col. Alexander Madiebo, Maj. Christopher Emelifonwu, Maj. Ayodele Ogunro, and Maj. Samuel Ogbemudia.After hearing that both Maj. Emelifonwu and Maj. Ogunro were murdered by Hausa-Fulani soldiers in Kaduna, Lt. Col. Kalu made his way to a railroad depot where he managed to stow away inside the water-tank of a train destined for south-eastern Nigeria.