Slaughtered to the last man. . It makes little difference how they were slaughtered.
Perhaps they did die in their beds as the result of Mexican perfidy . That doesn’t make the Americans look bad. More shame to the Mexicans.
Dead is dead.
It would not surprise me that many were shot at they were retreating off the front line. They could have sneaked out the previous night but they didn’t.
The only one to die in bed was James Bowie. And he had been bedridden for days. He was so ill, he may even have been dead by the time the Mexicans got to him.