I am currently working on designing an account settings page and within the current design, I do not hide the main navigation. Another designer I am working with is suggesting removing the main navigation once the user is on the account settings page and his reason is to not distract the user from the task they are trying to complete once on this page. The main navigation will introduce things like alert icons in the near future but I'm not sure a badge on the primary nav would be that distracting. Any opinions would be greatly appreciated.
I suggest you keep the navigation menu visible at all times.
The current design could hardly be called obtrusive. Even with notification icons I wouldn't imagine it would be much of a distraction, and in the event that the notification icons do draw the users focus... well, isn't that the whole point of them anyway?
Any slight benefits that you may think would be gained from removing this so-called distraction, would quickly be overshadowed by the inconsistency the user now faces with navigating the site.
Consistency is a huge factor in UX, if you are going to break it then you had better have a very good reason for doing so... this isn't one of those reasons.
As a side note, you may want to investigate the pros and cons of having a navigation menu that uses only icons, without text.