The Doctor: I swear this oath by Apollo Physician, by Asclepius, by Health... and by all the gods and goddesses. In whatsoever place that I enter, I will enter to help the sick and heal the injured. And I will do no harm.
The Doctor: In my preparatory report to the away team, I recall mentioning to you that Klingons lacked an enzyme for metabolizing this planet's vegetation. Have you been... naughty?
Lieutenant B'Elanna Torres: I had one small salad.
The Doctor: So impetuous. Any sharp pains?
The Doctor: Heartburn?
Lieutenant B'Elanna Torres: I guess so.
The Doctor: There's nothing like a heart that burns.
Mahatma Ghandi: Men and women should refrain from enjoying each other. By that I mean to say, even their mutual glances must be free of all suggestion of carnality.
Lord Byron: Free of passion? One might as well be free of humanity.
[while examining Torres' body, the Doctor gets very close to her]
The Doctor: Uh-huh... Mmm... Does that feel... good?
Lieutenant B'Elanna Torres: Doctor - unless you want me to knock you into the middle of the next millennium, you'd better back off.
[the Doctor has developed a dark personality]
The Doctor-Darkling: Watch your tongue - or I'll remove it.
The Doctor: I think I'm detecting a reaction to your recent break-up with Mr. Neelix. The Mahatma would recommend a cold bath. Simplistic, but no doubt effective.
Zahir: My course is as elusive as a shadow across the sky.
Lieutenant Tom Paris: So, what are you up to, Doc?
The Doctor-Darkling: [curtly] Work.
Lieutenant Tom Paris: Yeah, never ends, does it? I guess that mobile emitter turned out to be something of a mixed blessing, huh?
[the Doctor-Darkling studies his subroutines on a screen]
The Doctor-Darkling: Look! It's me. But it's also him. "What is the nature of the medical emergency?" What a hollow excuse for a life - servile, pathetic, at the beck and call of any idiot who invokes his name. The thought of him sickens me.
The Doctor-Darkling: There's not enough room inside for both of us. One must die. I deserve to exist, more than your Doctor does.
The Doctor-Darkling: I was born of the hidden, the suppressed. I am the dark threads from many personalities.
Kes: The historical characters?
The Doctor-Darkling: None of whom could face the darkness inside, so they denied me, suppressed me, frightened of the truth.
Kes: What truth is that?
The Doctor-Darkling: That darkness is more fundamental than light, cruelty before kindness, evil more primary than good, more deserving of existence.
Kes: Why does it bother you so much when I call you 'Doctor'? You said he was inside you, that he was unconscious. Why are you so afraid of him?
The Doctor-Darkling: I fear nothing! No one! But he... repulses me.
The Doctor-Darkling: Because he's as weak as the rest of you. He fails to understand the power of his own holographic nature. He is detestable.
The Doctor-Darkling: I am beyond considerations of wrong and right. Behavioral categories are for the weak, for those of you without the will to define your existence, to do what they must, no matter who might get harmed along the way.
[the Doctor-Darkling threatens to throw Kes down a precipice]
Kes: When I walked in on you on the holodeck, you could have killed me, knocked me unconscious.
The Doctor-Darkling: I needed a hostage!
Kes: You said you were taking me for my own good, to prevent me from making the wrong decisions. You said I was naive and needed your help. That's not what you say to a hostage. In your own way you've been trying to protect me.
The Doctor-Darkling: I won't accept that!
Kes: You've twisted and suppressed all that's good inside of you, but it's still there.
The Doctor-Darkling: No! I won't hear this anymore!
Kes: You can't deny it!
The Doctor-Darkling: Watch me!
[grabs Kes and plunges with her into the precipice]
[overtired, Kes hands Janeway a report]
Captain Kathryn Janeway: An all-nighter, Kes?
Kes: Uh, Captain?
Captain Kathryn Janeway: The fine art of putting off an important task till the very last minute, then rushing through it. In my Academy days, I was the acknowledged master.
[Kes tells the Doctor about her impressions of the Mikhal Travelers]
The Doctor: In my opinion, you've become far too infatuated with these Travelers. From the away team reports, they seem afflicted with terminal wanderlust, risk-taking thrill-seekers with no responsibility to the ideals of exploration. In short - bad news.
The Doctor: Would somebody care to tell me exactly what we're all doing here? And why I'm wearing these ridiculous clothes?
Ensign Harry Kim: Kim to bridge. We got them. And the Doctor seems to be back to normal.
[Security is keeping the Doctor at bay with phasers]
The Doctor: Put those down before someone gets hurt and I have to clean up the mess.