As an LS'er you are invincible in the tomb. However some encounters do kill you, even if they are not supposed to. Guess one glitches majorly on you.
Only bet here is using the Kotor Savegame Editor (KSE) (Link in sticky).
Open up your save and see if the Min1HP is set to 1. If not, do it. If already, just find the Hit Points tab and make it match Max Hit Points.
If you have to manually set min1HP, you might want to save after exiting the tomb and make sure it is once again properly turned off. Even though Kotor2 is easy, invernability everywhere is probably no good idea, unless you like to cheat.