At MIT, Dina Katabi and her team are working on a bold new way to monitor patients' vital signs in a hospital (or even at home), without wearables or bulky, beeping devices. Bonus: it can see through walls. In a mind-blowing talk and demo, Katabi previews a system that captures the reflections of signals like Wi-Fi as they bounce off people, creating a reliable record of vitals for healthcare workers and patients. And in a brief Q&A with TED curator Helen Walters, Katabi discusses safeguards being put in place to prevent people from using this tech to monitor somebody without their consent.