I think the worst part of Columbia was that they knew they were going to die on reentry, but they had only two choices, how they wanted to die.
When engineers saw the leading edge was damaged they know with 99.999% certainty that they were going to lose her during reentry. The crew had to make a decision on the 2 choices, die the slow death of asphyxiation and hypothermia, or ride it out and gamble the .001% chance the leading edge would somehow hold together long enough to get her down.
They made the same choice I would have, but I think I would have considered removing the suit while doing it. Given the options it would have just slowed down and prolonged the inevitable IMHO, best to go fast than taking the time to burn through the layers.
The engineers never "saw that the leading edge was damaged," and "they" (who?) never knew "they were going to die on reentry".
NASA could see from the launch films that there had been a foam strike on ascent. Their belief (not actually tested) was that such a foam strike wouldn't do anything more than cosmetic damage. It was deemed an "acceptable flight risk".
After the accident, they set up an experiment where they fired frozen foam pieces from a cannon at shuttle wing leading edges -- and blew big holes in the reinforced carbon-carbon that was the leading edge thermal protection.
Then they knew.
In retrospect, don't launch people on solid rockets (Challenger) and don't launch them on a spacecraft strapped to the side of a fuel tank, unless you're very sure (and have demonstrated by experiment) that that tank can't shed pieces that can damage the spacecraft.
NASA is still proudly violating that first rule (SpaceX certainly isn't!), BTW.