How we cite our quotes: (Sentence)
Quote #4
This Treaty shall be open to all States for signature. (18)
Mi casa es su casa, and the PTBT is for everybody.
Quote #5
Each Party shall in exercising its national sovereignty have the right to withdraw from the Treaty if it decides that extraordinary events, related to the subject matter of this Treaty, have jeopardized the supreme interests of its country. (28)
So, just in case things go belly up, the participating nations are still recognized as individual homelands (if not universally recognized as nations), and they have the option to opt out of the treaty for their own safety and security.