Eventually, Calvin and Molly turn their sights on the sheriff. There is a grim physical humor in the thought of two 8-year-olds trip-tripping over the ice to lay murderous hands on the "false Santa" himself, but it's quite difficult to kill a grown person -- as Adrian, a pediatrician, should know.
It's not that children cannot be seriously murderous. Take Roald Dahl's "The Swan," in which two boys torment a third, going so far as to lay him on train tracks, which he survives, before requiring him to fly, which he presumably does not. Dahl achieves quite credible terrors through the accumulation of small, discrete details, which build to an unbearable conclusion. Calvin too cheats death by lying under a train, but his survival owes a bit more to Camille. ("I want to live!" he cries.)
