I was the target demographic when this came out (or as close to is as makes no difference) and I don't remember being shocked or disturbed by that scene at all. Maybe it was the fantasy setting (vs. the average super-hero setting). Maybe it was the fact that the death happened off-panel. I don't know.
I remember being more shocked at the description of Aslan's dead body in The Lion, The Witch and The Wardrobe. And, to be fair, far more shocked and disturbed at my current age by casual on-panel violence and gore such as Black Adam pushing Psycho-Pirate's brain out the back of his head through his eyes.