My first yeast starter with a stir plate, possibly a disaster

This morning I smacked my first smack pack, and about 10 times, each time a little harder because deep depression would set in if the goodies spewed across the room. I finally got it, or so I thought. Fizzing away on the inside, it started to swell a bit about after an hour or so, and then 6 hours later, I sanitized my stuff, dumped it into my flask, all that good stuff... and it's doing its thing on the stir plate. It didn't swell up a lot at all, but also read about many people not bothering to even wait when they're using a stir plate.

So it's a 1L starter, that of which I'm going to chill in the fridge tomorrow, throw out the spent wort, and add some more to step it up.

Here's why I'm worried:

Out of curiosity, I tore open the packet to see the little stubborn pack inside that wouldn't bust very easy, and to my surprise, it's actually a double pack?! One half broke, whereas the other did not! It's a rectangular shaped pack, with two sides, each separate from each other. Is this some type of mixture? Or just double the amount for a higher gravity (which is what I'm trying to make)

So what I'm planning to do, unless someone can instruct me otherwise, is to throw in the contents of the second part of that pack tomorrow, when I step up the starter.

Please advise, and thank you... Loving this. Hope the non-swelling, and extra packet thing isn't going to ruin my starter.

Also, that little packet sat out at room temp all day while waiting for the pack to swell, but I put the little half of pouch that didn't bust in the fridge.