Everything goes almost accordingly

As you begin to despair, your lab assistant, Anna, seems unconfortable.
"Everything is alright ?" You finally says.
"Yes... yes..." she answer "... it's hot in here..."
"Weird, I'm fine, maybe you should take off that lab coat."
"Yeah, maybe you're right."
She take off the lab coat and stay in casual clothes.
"You can take off more, it's no big deal." You continue, just to test
"Thank's..." she says as she take off her pants and shirt. And she continue to work in underwear. She stop a moment.
"Something is not quite right." she finally says.
"You still wear panties and bra ?" You says.