grammar - Is this xkcd sentence grammatically correct?

So I saw this xkcd, and when I tried reading it, I always felt like the ending was a bit... unbalanced.

It says:

You're in a box on wheels hurtling along several times faster than evolution could possibly have prepared you to go. (Next 5 miles.)

I can't figure out what's wrong with it, though... it's as if some word (e.g. "at"?) was supposed to follow the word "go".

So I was wondering, is the sentence grammatically correct, or is it indeed missing something?
If so, what?

Answer

It's perfectly fine. Let's rewrite it to see what's going on.

Original:

You're in a box on wheels hurtling along several times faster than evolution could possibly have prepared you to go.

"box on wheels" => "car"
"hurtling along" => "going"

Creates:

You're in a car going several times faster than evolution could possibly have prepared you to go.

Now we can erase this unnecessary part:

You're in a car going several times faster than evolution could possibly have prepared you to go.

Finally creating:

You're in a car going faster than evolution could possibly have prepared you to go.

If you want to go even further, you can simplify all this to:

You're going faster than you are prepared to go.

Seems all fine here!