There would be some steam but mostly, it would stay as water.
The boiling point of water increases as pressure increases. So after a little water becomes steam which increases the pressure, the rest will remain as liquid.
If you continue heating the water past its *new* boiling point the water will turn into steam and the pressure will get higher and higher. Any real-world container will blow up.
Because the water is above its normal-pressure boiling temperature, as soon as the container breaks it’s going to very rapidly turn into steam and basically explode. This is called a BLEVE (boiling liquid expanding vapor explosion) and is extremely dangerous.
Latest Answers