Harry S. Truman signed executive order 9981 in 1948 integrating the armed forces. Most commanders ignored the order and the Korean Conflict was the last war in which the military continued to be segregated.
All black and all white units persisted during the Korean Conflict. However the all black units were considered inferior and suffered a disproportionate amount of casualties due to being assigned to more dangerous duty than their white counterparts
At the top of the episode, Charles lambasts Margaret for offering her medical opinion during triage, after which he reluctantly agrees with her diagnosis. He should not be so perturbed by her input, since in a previous episode, "Hot Lips is Back in Town" (1979), Margaret initiates a program to enable the nursing staff to assist in triage diagnoses to speed things along and free up the doctors to prepare for surgery. Therefore Charles should be used to the sight of nurses performing triage, though it may still do little to curb his haughty self-righteousness.
The title comes from the expression "the truth shall set you free."