The sheer amount of power and force as the numerous missiles continuously descend was something that Snow is unable to describe with words alone, all he just knows about is how much energies it needed to keep themselves and the Book of Origin safe and well protected during the nonstop assault.
Shadows and Ice power constantly breaking apart which he quickly tried to keep intact, making it firm and steady in order to guard the force of the powerful attacks.
If it was an ordinary missile then Snow wouldn't be having a hard time defending against the powerful explosion that it even cause him to sweat purposely, while his breathing becomes rapid by how much stress and pressure he is currently experiencing.
The sheer amount of how it was easy for it to rip apart his elemental power cause Snow to swear inwardly at the male protagonist's activities in the past.