The fear of death would be so well expressed not through images of murder, but also one's last agony, where it draws on and on and on (instead of being just a mere fleeting moment). The amount of iconography and religious imagery I have seen from medieval times onwards showing the last agony at death, and the emotions (anger, despair, yearning, difficulty to let go) that are so real that you don't want to succumb to them -- perhaps let us take inspiration from them for once? While we can't imagine what the fear is like....... well, until our own hour of death approaches, those icons were absolutely EFFECTIVE in showing just what the fear of death is like.
That being said, I applaud you for taking on the meaning behind this drawing. The fear of death is real, but not talked about often. The drawing itself is a bit sparse and could do with a lot more detail in the background to show just the many things that are going through the mind of the person soon to die.
Also, don't just cover beheading: cover hanging, impalement, crucifixion and all the other gruesome ways by which a person can die. Lynching and execution can be slow and painful, or quick and easy, but it doesn't matter: it ends up with the unnecessary loss of life. And I think it's about time someone brought a close to this government-sanctioned blood sacrifice.
What you did draw here, however, is quite good. The dilated pupils in that person's eyes, man.