Closeness
Garrigan becomes close with Amin after becoming his personal physician. Ironically, he has been lured in by the same seduction Amin has used to gain power and keep it - a seduction that is at its root sociopathic.
Marriage
Idi Amin has taken multiple wives and treats them as his personal property. Ironically, when Kay, one of his wives, betrays him (as he does to all of them) he kills her.
Dr. Junju
Dr. Junju knows the truth about what Amin has been doing in murdering the people of Uganda in order to maintain control of power. Ironically, he also knows that no one outside of the country will believe his story because he is a black man, and this is why he helps Garrigan to get out of the country - so that the world will believe the story since it is coming from a white man.
Physician
Amin brings on Dr. Garrigan to be his personal physician. Ironically, Amin begins to rely on Garrigan for matters beyond the scope of his profession, such as matters of state.
Belief
Garrigan discovers that Amin is killing people throughout the country. Ironically, Garrigan believes Amin when he tells him that he's killing the people so that there will be peace in Uganada, as they are the cause of the turmoil.