What kills you first in space?

The AI answer: "Without a space suit, a person would survive in the vacuum of outer space for about 15 seconds before losing consciousness due to lack of oxygen. The absence of atmospheric pressure would cause bodily fluids to start boiling and vaporizing due to the lack of external pressure, and severe tissue damage would occur. Death would likely follow within 1 to 2 minutes due to oxygen deprivation. Contrary to popular belief, a person wouldn’t instantly freeze or explode, but the conditions are quickly fatal."