"If I am slain," he replied so tenderly that Liand's heart lurched, "you will remain to serve the Land, and the Ranyhyn, and the Ringwielder, as you must. My love will abide with you. Grief is strength. The use that you will make of it vindicates me."
To me the present tense he uses in the word Vindicates means her predicted future actions and feelings for him vindicates him in his present action i.e. the saving of Jeremiah, not that he sees himself as already dead. It connects with what he says before:
"If I do not give of my utmost here, I will become less than my aspirations. I will prove unworthy of the gifts which I have discovered in you."
This is one of the greater chapters in TLC and I actually enjoyed reading it a lot. Together with the events underground at the end of part one it's surely the highlight of TLC so far.
However, I will probably never understand what makes Linden tick. Okay, she wants to rescue her son at any costs - something I can understand as a parent. But the way she tries to achieve this is beyond me.
There are three powers available at that time. The staff of Law, the ring and orcrest.
She has been warned not to possess Jeremiah. Using the staff she enters him nonetheless and fails. She had to fail and I'm sure we were all aware she would fail before she even tried - only she seems blind to the obvious.
She was also warned to use the ring for obvious reasons (the power not being controllable, Joan/raver will detect them, etc.). Again she can't see the obvious, failing again.
It has been mentioned countless times before that the croyel feared Liand. So it is not exactly rocket science to figure out that he and the orcrest are the weapons of choice against the croyel. I knew right after the creature's first reaction at Liand in the Lost Deep.
Why can't Linden see it? Because she's full of self-pity. If the characters would only just once get their sh*t together and act instead of rambling on the power of impotence, cryptic comments on contradictions and abstruse concepts of guilt, they'd have kicked LF lower backside long since.