Jack took the duel against Reepicheep seriously from the start, which meant that he immediately sheathed his sword in favor of scrambling up a nearby pillar to grab a flaming torch to use as a club and/or portable spark for throwing in the event Jack needed to make a quick exit and it might be advantageous to have a large, distracting fire burning behind him.

Unfortunately, Reepicheep interpreted this as Jack being an honorless coward and a buffoon who had no respect for mice.

Everything went downhill from there.