I take it you have a field for threat level and it has a value in it related to the current threat level for that form. You can add an open rule that switches views based on the value of that field as well.... Under Tools / Form Options / Open and Save there is a button you can click to add open rules.
I think either switching views or conditionally formatting sections is fine -- sometimes multiple views are a little easier when you are designing the form, 'cause you don't have to scroll down a great long form while you are working....