[Warning: this essay contains spoilers. Sorry, but I can’t make my point without them.]
My wife and I love murder mysteries; but I can’t help being amused whenever a famous and well-regarded author resorts to an impractical and wholly unreliable method of doing someone in.
G.K. Chesterton, in one of his Father Brown stories, has the murderer climb to the top of a very high church steeple and, from there, hurl a hammer earthward–expertly conking his victim to Kingdom Come.
Ngaio Marsh, in one of her Roderick Alleyn mysteries, has the murderer standing on a high cliff. Seeing his victim moving around in a pool below, he picks up a great big stone that requires both hands to lift, raises it over his head, and scores a bulls-eye on his target’s hapless skull.
Could you do that? Really, these murderers were wasted in civilian life. Either of them could have made a fortune playing basketball. I play basketball regularly, and on a really good day (which doesn’t happen all that often), with thousands of practice shots under my belt, using a nice, aerodynamically stable basketball aimed at a basket which is always in the same place and never moves, I might make half my shots from the three-point line–a much shorter distance than that traveled by either the hammer or the stone, with a moving target.
If it were me, I’d need a whole wheelbarrow-full of hammers and I’d miss over and over again. The victim would be well-advised to run away before I got lucky with a hammer. Ditto the big, hefty stone.
I suppose you can get away with this if you’re Ngaio Marsh or G.K. Chesterton. You or I would have nothing to show for it but a rejection slip and maybe a catty comment from an editor who’d had her fill of stories such as these. “Why didn’t the killer just hide a rabid sea lion in the trunk of the victim’s car, which would bite him when he opened it? Or simply arrange to bean him with a golf ball from 100 yards away?”
The same rule holds for any other kind of fiction, including fantasy.
Don’t ask your fictional character to do something that you couldn’t do yourself in 20 dozen tries.