Just because your kayak is puncture-resistant, does not mean that a leak will not present itself at some point. If it does, however, there is a high probability that you will not sink. Unless, of course, the abrasion is significantly large as this would probably cause it to deflate. To elaborate, most inflatable kayaks will be designed with a multitude of air chambers. If it is merely a small hole that presents itself, then the other air chambers should keep the kayak afloat. Again, a larger hole may become more of an issue but the multiple air chambers will still come into effect.
Truthfully, the only way you will end up sinking is if you pretty much destroy the kayak. As previously mentioned, they are built-to-last and to withstand abuse.