Or, maybe Yukimura will defeat Lyde. I think Yukimura should attack him anyway, even if it's just for a small chance of killing him. Plus, Yukimura shouldn't be knocked back in one turn. I hope so. And when Tsukiko's turn comes, we'll see.
The option "Tsukiko takes the enemy's sword" is only if Lyde has around 100 HP left after Yukimura's attack, then yes.