SICP metacircular interpreter question

How does it handle sequences in input? If it's in a define or lambda or begin or whatever then it follows those respective paths in the eval branch, all of which lead to eval-sequence. But if it's just
(define a 1) (define b 2)
how's it interpret that?

I'm asking specifically about the metacircular interpreter implemented in SICP 4.1. I can't find anywhere in the code which handles this, yet it works.