Never put the cart in front of the horse.
Lavos had better luck as a brainless monster. It's intelligence was its undoing.
I knew it! Distraction! Although, what made this a cleaver one was Samus being distracting to get Lavos to notice the distraction. Cool.
A lesson for all immortal supervillains:
Never leave a weapon, particularly a powerful sword made from an alloy of a mystical supercharged rock and shell of legendary proportions, stuck inside of even if it is particularly amusing to see the reactions of your foes. Because you're enemies, particularly if they're desperate will make full advantage of such a weapon.
It's my impression that the Lavos-X simply forgot about the sword.
maybe she'll channel the justice energy through the sword, destroying Lavos from within.
I think you have it exactly right. The sword would make a perfect conductor for the energy (Justice/Light) that would purge the corruption/Lavos from the suit, thus restoring Samus's suit and saving the day.
Hopefully, we'll FINALLY see Samus actually WALLOPING Lavos with that fist instead of just using energy shots and what not.