"What did you do?! We came here to stop the killing!! Who are you to take a life??"
―Michael Burnett to John Rambo.
Michael Burnett is the fiancé of Sarah Miller and one of the missionaries for the Christ Church of Colorado that went on a mission trip into Burma to give humanitarian aid to the Karen tribespeople, only to be kidnapped by the Tatmadaw Army.
Michael is a doctor and his medical skills help to save Lewis' life. Later in the film he has a change of heart after he kills one of the Tatmadaw soldiers to protect Lewis; thanking Rambo for his help.
Michael first appears when he arrives at the snake farm where John Rambo works there and asks for him to take them down the Salween river because the Tatmadaw have laid too many land mines on their usual route since their last visit. Rambo refuses because Burma is a war-zone, but Sarah persuades him otherwise. After Rambo kills all of the river pirates, Michael angrily reprimands Rambo for doing exactly what they came here to stop. Rambo grabs Michael by the throat and tells him that Sarah would have been raped dozens of times and they would have all been killed. Rambo attempts to turn back, but Sarah persuades him otherwise. When they reach their destination, Michael informs Rambo that he intends to report the murders of the river pirates, because "killing is never right". However, they are kidnapped by the Tatmadaw, suffering a grueling few weeks in captivity. Rambo organizes a rescue mission with the help of the church's pastor and some mercenaries, who invade the camp and rescue the missionaries. Lewis attempts to depart as their fifteen minute window is up, and Michael protests, demanding that they wait for Sarah. Lewis then grabs Michael and throws him to the muddy ground, holding a knife to his throat. Lewis tells Michael that "God didn't save your life, we did", before letting him up. The group leaves without Sarah, only for Rambo to rescue her personally, ripping the throat out of a drunk man who attempted to rape her. On the trek through the jungle, Lewis steps on a land mine which detonates and shreds one of his legs. At this point, Michael reveals himself to be a doctor and he gets the idea to make a tournaquit and a stretcher for Lewis. Rambo, Sarah and Schoolboy then discover later in the film that the Tatmadaw have once again captured the missionaries and now the mercenaries as well. Rambo rescues them by starting a massive gunfight with a Jeep-mounted .50 caliber machine gun. During this fight, Michael is forced to attack one of the Tatmadaw soldiers in self defense, by beating him repeatedly on the head with a large stone, injuring him severely, and most likely killing him.
After the battle, Michael embraces Sarah at the end of the film and thanks from a distance Rambo for saving their lives. He is shown to be a changed man after all the horrible events he has gone through.
Though Michael is undoubtedly a good person, as Sarah mentions, claiming he is always helping people; he is very religious, and his strong beliefs sometimes cloud his better judgement and get in the way of what is necessary. Though Michael is very even-tempered, he was angered after Rambo kills the river pirates to save Sarah and mentions that they should report him for it. Rambo tells Michael that, had he not killed them, the pirates would have killed them all and raped Sarah. Michael was intimidated by Rambo since he first met the man, and, though he did not dislike the man, told Sarah to stay away from him. Michael was not good at confrontation and preferred to simply shy away from situations where he would have to negotiate to get his way. Sarah was more persistent, however, and Sarah's persistence is why Rambo took them into Burma. Michael deeply cared for his missionaries, particularly his fiancée, Sarah, and everyone around him, as he always tried to help. Michael's ideas of helping people were different than Rambo's however, as Michael was a complete pacifist and did not believe in resorting to violence to solve problems, claiming that "killing is never right". However, he changes his beliefs after his experiences by killing a Tatmadaw soldier attempting to kill Lewis, a mercenary who was rescuing them. Michael later waved to Rambo as a silent thank you for all he had done for them, and Rambo never held a grudge.