"They tell that to the young rock hoppers when they go out on their first jobs."

The anti-nausea drugs common for Earthers and Martians weren't always readily available out on the Belt. At least not to the poor children of miners and metal-scrappers. And getting your 'sea legs', as it were, takes some time.

"Well...that and 'check your back.'"

A lot of Belter childhood was a foot out the door and the expectation that you'd either die soon or you'd die later.