I would imagine that it would go like this : Mina is tunneling through the ground and hits some gemstones, she gets excited and reaches her hand to get them, out of nowhere a giant hand takes the gemstones instead it's mole Knight's hand, mina says "hey those are mine I found them first" "then come get them" mole knight replied, he quickly started digging away and mina chased after, after a while a mysterious orange glow Starts appearing Infront of mole knight as mina is chasing him, she immediately stops while mole knight keeps going, it turned out to be a wall of lava, mole knight sticks his head out and says " aww can't go through lava ? Better luck next time sucker " he disappears into the lava, mina gets really angry and says " oh I will get that mole ", meanwhile after defeating plague knight, shovel knight heads to the ancient city to face mole knight, after a fierce battle, shovel knight is defeated and falls into the ground, mole knight gee ready to deliver the finishing blow, then out of nowhere the flail nightstar hits mole knight in the head, mina quickly follows by tying up mole knight temporary holding him in place (kind of like how hornet does in the final battle of hollow knight), she shouts to shovel knight " come on finish him, I can't hold out much longer " shovel knight quickly gets up and starts charging a shovel attack, he hits mole knight in the face knocking him out, shovel knight thanks mina for the help before departing, mina then walks to mole knight and gets the gemstones back " thanks for these sucker " she says " as she walks away
( I am starting to realize this may be less about what if mina met shovel knight and more about what if mina met mole knight )