Airbus APU autoshut down during auto engine start

[Tinwacker]

Dry cranking would only be necessary for the aborted start if the EGT had previously been rising , fuel light off.
An external air source is the only means unless the APU can be restarted after advice from engineering.
If the opposite engine was running then cross-bleed would be the preferred choice to cool the aborted engine for speed.

All airports I have been at will not allow the aerobridge to connect to an aircraft with a running engine.
Maybe the crew should review the MEL for APU and make a decision about whether returning to the bay is an option in this case, call maintenance control for further advice perhaps..