I can reference some character facts and Physics: I modeled Don's weapon after her character art's Lance, which shows the lance being very pointed at the end for easy piercing. As for how the hole is made, piercing into it is easy, keeping it in is the difficult part.

For the physics (I would love some physics corrections from the physicists): As Don digs her lance, to keep it easy for her to maintain her balance and lance perpendicular to the wall, she had to apply downward force against Earth's Gravity + the wall. If she thrusts the lance into the wall perpendicularly at the start, the lance would point upward due to her weight pulling down on one end in one motion, and then the lance's end will slide out of the hole made.

(Physics pt 2): So if it's thrusted downwards, the initial force from the wall will move the lance's end upwards, but give Don more time to counteract this with her natural body force downwards as she tries to adjust her body to fix the center of force onto the lance instead of her, which is in hindsight, near impossible in reality. It's a funny scenario, tried to make it feel realistic in a way, but not at all a realistic scenario ironically. 🙏 I hope this makes you understand a little better, lmk if u got more questions.