[quote=@Feisty-Pants]
<Snipped quote by Raijinslayer>

The walls are, not the top. The top is much, MUCH thicke. 
[/quote]

Hundreds of feet of ice in a matter of seconds. . . I'm not an expert on the rules and limitations of the anime, but that seems like a little much for even a level 5 unless they have some sort of equipment. Hell, if you can do something like that, why would you even bother fighting Jack when you can just freeze him in a snap without a worry. Also, if it's not sone in seconds, then would that leave you open to an attack from Jack before you can make your own. I'm just saying, when in a battle, you should spend a lot of time not paying attention to an enemy, especially just to keep out two possible allies.