Throughout this episode and the next, several characters state that they were "only following orders" or "I have orders to follow." HYDRA was originally a Nazi-offshoot organization. "I was only following orders" was a defense used several times by Nazi officers and soldiers at the Nuremberg Trials.
When Coulson uncovers the Cybertek files on the Deathlok program, he notes how the program goes back to the 90's. The original Deathlok (Luther Manning) was introduced in 1974, but set in a post-apocalyptic future of 1990. The second Deathlok (John Kelly) was introduced in his own comic series in July 1990.