Conversation so far:
When did James Stockdale become a prisoner of war?
On 9 September 1965, while flying from USS Oriskany on a mission over North Vietnam, Stockdale ejected from his Douglas A-4 Skyhawk.
What happened while he was a POW?
Stockdale was held as a prisoner of war in the Hoa Lo prison (the infamous "Hanoi Hilton") for the next seven and a half years.
What happened during those 7.5 years?
Tortured routinely and denied medical attention for the severely damaged leg he suffered during capture.
What else transpired during his time at Hoa Lo prison?
Stockdale created and enforced a code of conduct for all prisoners which governed torture, secret communications, and behavior.
How did he escape being a POW?
CANNOTANSWER.
What else happened during his time as a POW?
Early in Stockdale's captivity, his wife, Sybil Stockdale, organized The League of American Families of POWs and MIAs.
Was there anything else that happened while he was a POW?
In the summer of 1969, he was locked in leg irons in a bath stall and routinely tortured and beaten.
What else happened while he was a POW?
When they covered his head with a hat, he beat himself with a stool until his face was swollen beyond recognition.

Question: What else took place in this prison?
Self-contained rewrite: What else happened to John Stockdale in Hoa Lo prison other than denial of medical care, and Stockdale's creation of a code of conduct for all prisoners?