Solution

This shows that the particles of matter have spaces between them and the interparticle forces of attraction between liquid particles are not very strong hence the force applied by diver is enough to overcome these forces of attraction.
Key to this answer is that a diver will be able to pass through water if there is availability of space between the particles and the forces of attraction between the liquid particles are not very strong. The diver will not be able to cut through solid ice because of less spaces between the solid particles and strong forces of attraction.