Can the emission of pure semen from the impure urinary tract be considered evidence for the excusability of slight impurity?

Those who advocate for pardoning a small amount of impurity argue based on the lifting of hardship (رفع الحرج), the difficulty of avoiding a small amount of impurity, its widespread occurrence (عموم البلوى), and by analogy with the traces of impurity that are pardoned in the context of istijmar (cleaning oneself after defecation). Just as a brief moment of impurity is pardoned, so too is a small amount of the impurity itself, such as someone upon whom impurity falls and who immediately removes it—their prayer is valid. However, arguing for the pardon of a small amount of impurity by claiming that impure urine does not affect the purity of semen despite their shared exit point does not seem to have a clear basis.