The truth is Ben doesn't know enough about science to say any different; his dad had only educated them on topics that he thought would be useful for saving the world, and that didn't lend itself towards complete or systematic learning. He'd done a lot of additional reading on his own, but for that, he gravitated towards fiction, not the sciences. So if Cho says the same fundamentals apply, he buys that.

It ends up being useful, just how frozen in place Ben is. He stays still, and silent, dark eyes following Cho as she approaches the little guy, talking in that sweet and quiet voice, getting its attention with the smell of food. Clear she's worked with animals before. Clear she really does like them. The whole scene is, frankly, adorable. He knows he should be feeling adorable about it. Maybe if it were a good day and his brain started off in a good place, but it hadn't.

So he hangs back as she coaxes and flatters and bribes the little rodent to come to her, gentling it and speaking to it and feeding it apple bits, before she gets it settled into a little sub-container within the carrier. Like its own little apartment, complete with more apple treats for the road. It's the cutest thing, and Ben hangs back, watching with his arms crossed tightly, hands gripping above his own elbows so hard his knuckles are pale. But he's got this on lock.

Once she stands up again Ben manages: "Why marine science?"

He wants to keep the conversation going, but saying the words requires a little bit of wrestling out, some internal contorting to try and make them sound close to normal, like his heart isn't racing and he isn't trying to fill the silence in an attempt to distract himself from being stupidly upset about stuff that is long-past that shouldn't even matter anymore.