despite being a very sensitive person, growing up & as an FBI student / recruit, holden’s never been bothered by pictures & other footage of murder scenes. his very first experience with death, however, occurs at the show’s opening sequence, where holden is caught up in a HOSTAGE NEGOTIATION situation, trying to convince cody miller ( the abductor ) not to take his own life. his failed attempt ends in miller’s suicide, a gun to his head. holden witnessing the whole scene from just a few feet away.

it’s important to note that holden gets EMOTIONALLY INVOLVED real fast & takes things to heart. he sees miller’s suicide as personal failure & thoroughly blames himself for his death ; one that could have been, in ford’s opinion, prevented. he consequently falls into a minor depression, as is revealed by the following scene, where his boss, shepard, informs him he is re - assigned him as a teacher to keep him busy & focused.
another sign of this trauma happens a few scenes after, while holden’s exercising on the quantico tracks & other recruits practice FIRING their guns in the nearby shooting range :

the loud BANG that echoes is enough to drag him into a brief state of panic, which he manages to keep hidden from his colleagues. but it’s really witnessing the act of suicide that TRIGGERS ford. throughout the majority of the season, he’s confronted with numerous graphic pictures of murders / dead bodies & is required to go out on the field to INVESTIGATE first hand ( being then privy to gruesome accounts from victims’ relatives & criminals alike ) & while he’ll display empathy towards most interviewees, he never seems fazed by the pictures or the oral descriptions themselves.
i believe holden will get far more personally INVESTED ( emotionally as well as physically ) in a murder scene he’s been the witness of, as shown not only in the scene at the very beginning of the season but also the entire episode spent at the fredericksburg elementary school, trying to figure out the best course of action when he realized how deviant the principal’s behavior turned out to be. ━ the very same goes with being in contact with a dead body.
━ HC ASKS ( ALWAYS ACC’ING. ) / @aboutwinning.