Legolas hates caves. Always has, always will.
They don't know why they hate them so much, and they don't know why the palace of Mirkwood doesn't seem to count. Their best guess is that it's well-lit and lived-in, but they don't know.
They do know why they don't like Moria specifically: It's dark and damp, and the air is stale, and they can hear the creaking of Durin's Bane (and sweet Eru, that voice makes their stomach twist in what would be paranoia if it weren't justified), and it's been sixty years but death lingers like the carvings in the stone walls.
Gimli loves it here. Legolas wishes they could too.
It is now so dark that even Legolas can barely see.
They called it nerves an hour ago. Now, they'll admit that they're terrified.
(Gimli is still perfectly confident. Legolas stays near the dwarf, acting as calm as they can. Gimli acts as a pillar of strength, just as they hoped — but the churning in their stomach doesn't go away.)
In a way, they're almost grateful for the Orcs and the cave troll. Paranoia is a subtle, creeping thing, and the adrenaline from fighting flushes it out better than reassurance ever could.
Then the Fellowship finds the tomb of one of Gimli's family, and they stop being grateful.
They knew it was bad, but they didn't know it was this bad.
The Fellowship is surrounded by orcs. Tear tracks coat Gimli's face, soaking into his beard, and Legolas doesn't hear what he screams but the battle is rough and clear and fast and they don't need to.
And then they reach the Bridge, and Legolas's worst nightmares take shape.
Gandalf is dead. Legolas knows this, in their head, but is still vaguely shocked.
The hobbits are crying. They think, absently, that they should do something about that. Nothing suggests itself.
They keep Gimli within eyeshot at all times. Maybe they can absorb a bit of his strength.