는다고

Repeats a claim, often disbelievingly

This attaches to an action verb and marks the words as something quoted. Most of the lines here throw someone else's statement back at them as an astonished question: one asks whether the other person is really looking for a scalpel, another whether they are going to eat all of it by themselves. Said flat instead of as a question, it restates your own words insistently, as in the line about never holding hands no matter what. Adding 요 gives the polite 는다고요, which is the same move in a politer voice.

Register: casual spoken; add 요 to be polite