Pft. You can take shots of fireworks without a tripod; evidently, because this guy did it. Not advised, but I've managed to hand-hold a two-second exposure with minimal loss of sharpness (it's all about stabilizing yourself so that you're the tripod). Crazy? Yes. Doable? Sure. Fantastic results? No. Usable results? Yup.
Anyway, the third and fourth do look pretty funky from the hand-holding. Next time, bring a tripod.