How does current flow in the short circuit? Aren't the two ends at the same potential?
Try looking at it the other way.







simulate this circuit &ndash; Schematic created using CircuitLab

Ask yourself what would happen if current didn't flow in the short-circuit.

The answer is that the potential difference across it would rise. If the PD rises then current will flow.

The circuit settles down with current flowing. All the rest of the wiring in the current loop is a short-circuit too.