Not That

Hi.

Wouldn't you need a punctuation such as a long dash (or, short dashes or a semicolon) between 'too' and 'not' instead of the comma? Or, wouldn't you want to end the sentence with 'too," and start a new sentence with 'Not that'? At first reading, I was a bit baffled by this 'run-on' there. If this was okay, then wouldn't "Not that she had the slightest idea of what, if anything, she was supposed to watch for, the puppies seemed healthy, too" stand okay, too?

(Gabby's dog, Molly, had gone through a very difficult delivery of puppies the night before. Both Molly and her babies were fine now)
Saturday morning started out well --- as the sun came slanting through the blinds, Gabby found her fuzzy pink slippers and shuffled to the kitchen to pour herself a cup of coffee, looking forward to a leisurely morning. It was only afterward that things started to go wrong. Even before she'd taken her first sip, she remembered that she needed to check on Molly and was happy to find that she was nearly back to normal. The puppies seemed healthy, too, not that she had the slightest idea of what, if anything, she was supposed to watch for. ("The Choice" by Nicholas Sparks)

Hiro