Ryan is not actually a Grimm. He is a Lebensauger (a Wesen) who suffers from extreme self-loathing. He obsessed over Grimm history to the point of killing his own kind to "prove" he belonged with the Grimms. Key Themes for a Paper/Analysis
The police department is compromised from the inside by an intern who uses his access to stalk and manipulate the lead detectives. Other Possible References [S2E10] The Hour of Death
Analyze Ryan's psychological state. He is a Wesen who wants so desperately to be a "heroic" Grimm that he becomes a monster to his own people. Ryan is not actually a Grimm
If you were referring to a different "[S2E10] The Hour of Death," there are a few other possibilities, though Grimm is the most prominent: though Grimm is the most prominent: