... In fairness, the Mexicans were maybe being prudent in making a temporary surrender, er, withdrawal.
Per my buddy at the Museum of Arizona History - At the time the Mormon Battalion headed towards Tucson, the garrison in Tucson was a shadow of the force the Spanish kept there in the past - between 30 to 40 reuglars supplemented by a similar number of part-time militia. Most of the regulars were effectively militia themselves, holding down part-time jobs in the small town of Tucson or prospecting for gold or silver in the wilderness of Southern Arizona.
I think discretion would be the better part of valor in this case. There are a few Mormon Battalion monuments scattered around southern Arizona, including the presumed site of The Battle of the Bulls.
Frankly long travel in the days before antibiotics, motor vehicles, and antiperspirant must have been horrendous.