Well, I typed a lot in response, but it amounts to far too much highly subjective evaluation of what Maytag said and how it relates to the rest of what she said in that speech box or even to what she said in the other panels' speech boxes for it to be worth Brion reading. As I said in the first place Maytag could simply speak that way, and to expound upon that it could simply be that she spoke that way at that time rather than speaking or meaning to speak that way at all times.
Your alternative ("One moment you feel like you're in an oven; the next moment, you feel like you're in a blizzard.") to what Maytag said uses a semicolon, which I rejected out of hand when making my post for being "unnatural" speech, especially when it's hard to convey that you used a semicolon to a listener, which is the context I am using for Maytag's speech to her audience of characters in the story. I don't know why you put a comma after "the next moment" in your alternative, either. Your example needed no comma after "as if to say", nor would anyone ever normally put a comma after ", and", to relate back to conjunctions.
Anyway, your example (The cold ice blanketed the frozen tundra, as if to say that nothing in life would ever be warm again.) doesn't work well for me at all, because you changed so many things so greatly. You decided to change what Maytag used to "as if to say", and then followed "as if to say" with figurative speech meant to enhance the first part of the sentence, which is definitely not what Maytag was doing, as she was merely descriptively listing multiple occurrences. These occurrences contrasted with each other, but were nonetheless independent from each other. Your example instead contained one occurrence (and hence no listing; Maytag was actually listing occurrences for the bulk of that page) followed by technically unnecessary (from the perspective of relating occurrences) figurative language. At best I could relate your example to either part of the sentence (each having an occurrence with a level of figurative enhancement, although less figurative and more descriptive relative to your example), but not to the complete sentence, which would make the conjoining unrelated, as this comes after a complete part of Maytag's sentence, but in the middle of your example. I also have never seen "the next moment" used under Maytag's circumstances, so it's definitely not going to feel natural to me unless you can make it make sense using more directly comparable example sentences than the one you gave.
EDIT: I still think your example was inadequate, but perhaps the gist of things is that "the next moment" is similar to just saying "then", but she didn't actually say "then", so I don't think of it the same way. I avoided suggesting replacing anything with "then" in the first place, too. It just feels too awkward to me in some sense to treat "the next moment" as if it was "then". I guess you can get away with listing things with just "then", but it's awkward to me to just let anything that functions similarly count as being "then". "Then" itself in this sense is an adverb, but thinking of the phrase "the next moment" as actually being an adverb is a bit much for me. How abstracted from the normal way of speaking can one get before something becomes "unnatural"? For example, would it be fine to say "One moment {}, another moment {}.", too? It gets weird at some point!