[quote=Voltaire]
His equipment is fine but I'm pretty sure that's not the issue. It's one of those 'you made the wrong choice' things I think because I don't use him in the fight at all. After killing the the reaper I'm just treated to a cut scene of him dead on the ground even though he was fine just a minute ago.
[/quote]

Who was "holding the line"? There is a lot of factors to the survival of Mordin-- strength of the line, equipment quality, loyalty, etc.

I've had Mordin in the same scenario alive PLENTY of times.