That line is also included in the verse, Mick (!) in bold:

Buying bread from a man in Brussels
He was six-foot-four and full of muscles
I said, "Do you speak-a my language?"
He just smiled and gave me a Vegemite sandwich
And he said,

"I come from a land Downunder
Where beer does flow and men chunder
Can't you hear, can't you hear the thunder?
You better run, you better take cover."


Lyin' in a den in Bombay
With a slack jaw, and not much to say
I said to the man, "Are you trying to tempt me
Because I come from the land of plenty?"
And he said,

"Do you come from a land Downunder?
Where women glow and men plunder?
Can't you hear, can't you hear the thunder?
You better run, you better take cover."
Yeah!

Living in a land Downunder
Where women glow and men plunder
Can't you hear, can't you hear the thunder?
You better run, you better take cover!