Yeah he has every fucking right to reject you, cause evolution seems to be a very dangerous subject. Worst you could do is kill the guy or make it rampage, and even then what about the other resources he needed?
Literally I would be yelling at her for her stupidity. She's lucky it was what was needed (how could she know when barely anyone else does. Heck you even despised the monster being low rank, that you somehow didn't know all these years?)