With Mortality essentially being a torture!fic and various other one-shots written in that vein, there's definitely some disturbing stuff.
- Holmes's canonical conversation with Culverton Smith gets a rewrite from Holmes's Point of View. He's dying with Smith gloating over him - needless to say, it's a pretty intense, heart-in-your-throat scene. Though it ends badly for Smith.
- Some of Holmes's torture scenes are longer and more graphic than others, but none of them are fully played-out. This might be considered a case of Nothing Is Scarier - especially the poker scene, which is only mentioned afterwards and never described in-detail. All we know is that Sherlock screamed his brother's name.
- In one scene, Holmes has another Flashback Nightmare and is snapped out of it by Watson, who then soothes him back to sleep when he doesn't want to go back. Watson unwittingly sends his best friend back to his nightmares.
- Speaking of dear, dear Watson... Beware the Nice Ones. He feels no compunction in terrifying a criminal into talking and then shooting him when Holmes's life is on the line.
- When the narrative looks at Holmes's rescue via Lestrade's POV, Holmes's appearance is described in detail, including this: his gaunt face bruised, burnt, and scarred, his half-clothed body far more so and this: The ragged shirt [...] hanging in tatters on Holmes's truly emaciated frame. Clothing Damage. Does This Remind You of Anything?
- The bullet-pierced corpses of Mary and her baby in "Those Dark Hours". The author hated herself for writing that...