SORT OF! it's a little bit of a complicated situation, but he is moreso an "accomplice" to a serial killer more than anything. after he becomes entangled with vadim [javi's character], someone who is a genuine serial killer and whom has a trail of bodies spanning his time in russia and america, he slowly reveals his "proclivities" to him over a period of time. after he is hired at the same hospital vadim works at with a few falsifications here and there, shawn is then given the full reign to enact any and all violent impulses he's ever considered.

vadim is fully under the impression that shawn is capable of the exact same things he is, "testing" him and "fostering" this newfound outlet with more extreme and intense methods; encouraging him to start small with morgue visits for "exposure" to the dead, then comatose patients, braindead patients, and then conscious patients, inducing live-infections, surgery "slip-ups", IV & medication spikes, etc. for vadim, it's all part of the fun.

for shawn though, it does end up backfiring, as while he is obviously not exactly a good person, with a host of behavioral problems & questionable ethics, not to mention the parasite fetishization, there are alot of mental aspects of his character that are left unchecked / unattended to that stem from deeper childhood neglect, inferiority issues, lack of resources, spiralling into bad crowds, etc. because of this, he does still retain a majority of his conscience, and whether he realizes it at first or not, he'll soon find out he isn't entirely cut out for this life. and these consequences /will/ sneak up on both of them, no matter how untouchable they think they are.