- Docked Columbia at the ISS,
- Moved the crew onto the ISS (potentially saving their lives),
- Conducted more analysis of the damage there, while
- Giving NASA more time to ready Atlantis or Discovery to bring them back, or even have the Russians ready a Soyuz rocket.
That gets the crew somewhere that they would not be in danger of something catastrophic (like what happened to Columbia), at the cost of a bit more space and time in orbit. All could have made it back to Earth alive.
But that's just me, and I may be totally wrong.