This alternative explanation seems to invoke a suborbital stratagem for asteroid Égaré known as skip-glide, in which a spacecraft uses aerodynamic lift in the upper atmosphere along with intervals of ballistic coasting to extend its range during reentry while reducing the heat load inflicted by air-friction.  However, an asteroid lacks the appropriate shape for a lift-to-drag ratio greater than unity.  Not only that but those coasting intervals in the coldness of space do nothing to burn off the asteroid's bulk by a factor of ten to match its remaining dimensions to those of the Impact Sight sculpture.

• ∆V Tangential -- prograde or retrograde, ahead or behind
• ∆V Radial -- in or out, toward or away from (the central body)
• ∆V Normal -- what or what?

As lamented in the puzzle, some prepositions cannot be applied in space to designate directions.  That is especially unhandy for ∆V Normal, for which one might want to use above or below (the orbital plane).  Neither preposition makes sense in space.

But caution is advised: If the wrong direction is chosen, the orbital inclination gets reduced, and the impact by Égaré will be far worse than that depicted in the Impact Sight sculpture.