More important is the fact that Sam Houston had, days earlier, ordered the mission evacuated, the men there to join his own army further north; by defying his order the men of the Alamo were staging a sort of mutiny.
Although it is very common, north of the Rio Grande, to regard Antonio Lopez de Santa Ana as a deep dyed villain, but to Mexicans he is their George Washington. It was Santa Ana who played a vital role in ousting the Spanish and later Maximillan from Mexico. He was president, or generalissimo, of Mexico a number of times. In fact, it was Santa Anna who triggered the Texas War for Independence by abolishing slavery ... the defenders of the Alamo were defending the institution of slavery.
Despite the ugliness of the Siege of the Alamo, the US govt allowed Santa Ana to stay in the US in his two or three exiles between presidencies. One of his last US sojourns was on Staten Island, NY. He brought with him from Mexico a bitter root that he enjoyed chewing. He called it chickle ... his secretary, a man named Adams, used it to invent chewing gum.
I was taught in High School Texas History that Col. Travis made the stand at the Alamo to buy Sam Houston's Army more time to assemble volunteers to face Santa Ana.
I'm left wondering about your motives in cheapening a great act of heroism by referring to it as "a sort of mutiny."