Mars Attacks: Denver Vs Detroit

[Enzzo]

I have a rules question.

Player A had captured Denver, which allows you to reroll if you nuke out on your first turn. This player was trying to capture Detroit, which requires you to capture it all on one turn or you are nuked. There were a total of 6 nuke spaces on the board at the time. The player rolled 5 nuke dice on his first roll; since Detroit requires 6 guns to be captured, this result made it impossible to capture in one turn, meaning that the player was nuked, after having rolled the dice once. Is the player entitled to reroll the dice using the Denver ability?

Thanks :)