English resources/Dr Jekyll and Mr Hyde/Science
Jekyll uses chemistry to do what should not be done. Lanyon sees it and dies of the shock.

6 quotes, in the order they happen.
the man seems hardly human! Something troglodytic, shall we say?
Utterson · Chapter 2: Search for Mr Hyde · evil · science
Hyde seems less than human. Like a cave man. A creature from before people.
the moment I choose, I can be rid of Mr. Hyde.
Jekyll · Chapter 3: Dr Jekyll Was Quite at Ease · duality · science
Jekyll thinks he is in control. He can stop whenever he wants. He cannot.
I have had a shock," he said, "and I shall never recover.
Lanyon · Chapter 6: Incident of Dr Lanyon · science · secrecy
Lanyon has seen something. He will not say what. He dies of it.
O God!" I screamed, and "O God!" again and again
Lanyon · Chapter 9: Dr Lanyon's Narrative · science · religion · duality
Lanyon watches Hyde drink the potion and turn into Jekyll. He cannot stop screaming.
My life is shaken to its roots
Lanyon · Chapter 9: Dr Lanyon's Narrative · science
What Lanyon saw broke everything he believed. Science, God, all of it.
the animal within me licking the chops of memory
Jekyll · Chapter 10: Henry Jekyll's Full Statement of the Case · evil · science
After the murder, part of Jekyll enjoys remembering it. Like an animal after a meal.