Trisha mentioned that my semen was something extraordinary. Out of curiosity, during one of our fucking sessions, she decided to scoop up some of it from her pussy and do a little research. She discovered that my cum had magical properties, with an unusually high life potency. Maybe it was because I was a creation of the Great Red, a.k.a. Lilith, that my sperm had potential powers. While it might be an exaggeration to say it could bring someone back from the dead, it was definitely possible to create a life-saving medicine from it.
Trisha could have made a medicine from my cum and had Melina drink it, which would have been a lot easier than taking it straight. But it was still semen, and Zeruel couldn't possibly stomach the idea of making Melina drink something like that.
Besides, there was no guarantee it would actually help her.