[Central Date 93212]
The Stealth Craft had already arrived in Celine one week earlier before the departure date of David to Kermurkheim.
And the pilot of that Stealth Craft had given a crash course to David regarding the several functionalities of that craft. David had risen up to the post of the Captain of the Voyager by starting off as a pilot of it. So it was not hard for David to grasp everything in that short duration of time.
As General Vesper had mentioned before about adding an extra function of self-destruction, the modification had already been made to the Stealth Craft in such a short duration of time.