Well, Byron's arrow was made from bamboo. Yup. Bamboo: sort of a nuisance if you've got too much in your garden but it's an eco-friendly boon for cheap, snazzy flooring, disposable dishes and weirdly comfy fabric. And arrows.
If you picture it, it's basically tubes connected at joints, right? So, when this arrow broke, it split on those nodes, of which there were three. And it did a funky thing: It Robin-Hooded itself.
For those that ain't hip to the lingo, Robin Hood won a Silver arrow in a tournament by splitting a sprig of wood with his arrows. Twice. From there, it's become a bit of a trope in archery movies and stories. When someone hit's an arrow with another one, that's a 'Robin Hood'. The first time, you're pretty proud of yourself. After that, you're proud of yourself and pissed that you broke the first arrow which is usually your own. (Or so I hear.) You might picture the dynamic movie shot of the first arrow being split back to front, but what's more usual is 'telescoping' because most people have aluminum arrows. In that case the second gets plugged into the back of the first. Actually, Mythbusters proclaimed you'd really only be able to split it from end to end with a hollow arrow, as in, (ahem,) bamboo. But here, we have something a little deliciously weird...
Byron's arrow hit a nail and the bamboo segment behind shoved itself into the forward one - SPECTACULAR. As a bonus, he's probably not too upset at losing it. From what I've seen, Byron's pretty into perfecting the art of making arrows, so he can afford to do it a few more times!