Is there only an issue of style difference between the following sentences:
If he had to describe himself in five words, he'd say he's curious, forgetting to give you four more words.
If he had to describe himself in five words, he'd say he's curious. And then forget to give you four more words.
Does it make sense to think that the second example emphasizes that he has forgotten to give four more words, rather than that he is curious?
Note: I'm not sure whether the first one is grammatical, and the second one is very hard to understand for a non-native English speaker.