Read the ranks as a straight line
High-end track: Jack → Queen → King → Ace
Low-end track: Ace → Two → Three → Four
These are two separate linear placements for the ace. They do not join at the ends. Therefore, a same-suit Jack, Queen, King and Ace can form a high run, while a same-suit Ace, Two, Three and Four can form a low run.
Why queen–king–ace–two fails
Hypothetical example: suppose the cards are the Queen, King, Ace and Two of hearts. The first three have consecutive high-rank order: Queen → King → Ace. The Two is not the next card after Ace in that high placement. It belongs only after Ace when Ace starts the low placement, where the order is Ace → Two.
So the proposed sequence would need the ace to occupy both roles at the same time: the final card after King and the first card before Two. A single card cannot repair that gap. Even if all four cards have the same suit, Queen–King–Ace–Two is not one valid run under this scoped rule.
Sorting as 1 or 14 does not change adjacency
A hand display might sort Ace as 1, producing Ace → Two → Three, or as 14, producing Queen → King → Ace. That is only a presentation choice. If Ace is treated as 1, it cannot follow King; if it is treated as 14, it cannot precede Two. Changing the number used for sorting does not create a connection between the two endpoints.
Self-test: keep the suits constant
Hypothetical check: compare Ace–Two–Three of diamonds with King–Ace–Two of diamonds. The first passes because it follows the low track consecutively. The second fails because King–Ace uses the high end, while Ace–Two starts the low end; the ace cannot join both tracks in one run.