Agents of S.H.I.E.L.D., Season 1

Coulson:
She took it upon herself to get them out. Said she could fix the problem. So she went in, crossed off the enemy force, didn't say how.

Skye:
Did she lose anyone in there?

Coulson:
Herself. May used to be different. She was always quiet, she just...she was warm. Fearless in a different way, getting in trouble, pulling pranks, thought rules were meant to be broken. Sound familiar? But when she walked out of that building it was like that part of her was gone. I tried to comfort her, but she wouldn't tell me what went down in there.

Skye:
What did you say?

Coulson:
I said the words I thought she needed to hear.