The comment box is not part of the answer options. It is not connected to any of the answer options, nor to yes, neither no, so it doesn't make sense to have "exclusive" options for this. Because all answer options in a list radio are exclusive by default.
There are a couple of solutions though:
1. What you are actually looking for is not "List Radio with comments", but a comment field that appears when people give a certain answer. So you should use 2 questions (which they actually are), one List (Radio) and then via relevance equation you show/hide a text question depending on the answer
2. Use the "other" option for the answer option that should require a commetn (but not a good solution in my opinion, 1. is a lot clearer and better)
3. Maybe you can use validation to alert people who should not answer the comment (still, I think solution 1 is the best)
4. Ignore the comments given by those that answered "no", because you wouldn't have the comments anyway (still 1 is better).
So i don't think there should be an exclusive option in single choice questions. You should use the correct question types.