I think it is because of hormonal imbalance like what you
said... the hormone involve in squirting or producing milk is
prolactin and that comes from the anterior pituitary glands. The
sole hormone inhibiting prolaction (hence from milk squirting) is
dopamine (which reduces during depression and isolation).
I think this can be applied to them soldiers who are POWs and kept
in the dark prison, with no light to see and no hope to hope for...
The dopamine levels may be reduced and hence leaving no inhibition
to the prolactin levels which leads to hyperprolactinemia and
explaining the milk formation in the male's b.reast.
Interesting Fact:
1% of male can get b.reast cancer
Out of the 1%, 100% of it is malignant
Furthermore, it is deadly and fatal, because the region of spread
(unlike the female breast) is smaller and it takes a rapid route to
enter the bloodstream...