Season 4, Episode 20: "The Junior Mint"

Over the balcony, bounced off some respirator thing...

...into the patient.

What do you mean, "Into the patient"?

Into the patient. Literally.

-Into the hole? -Yes.

-Didn't they notice it? -No.

-How could they not notice it? -Because it's a little mint.

It's a Junior Mint.