I think it also has something to do with how they both hit their respective watermelons. Siyeon held hers in place with one hand and hit it with her other hand. Aisha just hit hers without holding it in place. I think Aisha's hit was more concentrated on a certain portion of her watermelon given how she hit it, while Siyeon's hit was more blunt since she held her watermelon in place while she hit it. Since watermelons are oval shaped with a solid malleable exterior and a softer fluider interior, a concentrated force is more efficient in cracking it open instead of a blunt force. While I admire the strength of both idols here and I'm not claiming which one is stronger, just because Aisha got to break her watermelon doesn't necessarily make her hit stronger than Siyeon's.

Yunjin vs. Yujin perhaps

@@kentvesser9484 yeah, between two little devil 😈 also