A man near to me - I did not understand his words - he wouldn't eat so the pale men took him out through the hole in the roof. We think they put hot rocks to his mouth. Now his lips are so burnt he cannot speak or eat. I must try to eat.
These are shackles or leg irons. They limited slaves' movements and allowed a few slavers to control many captives easily.
Some captives refused to eat in an attempt to kill themselves. However, they were seen as cargo that needed to be kept alive so were force-fed. Some had teeth broken, others had their jaws prised apart with special scissors. Some, like the man Okechukwu sees, were brutally punished.
Captives tried other ways to end their misery. Some tried hitting their heads against the ship, others jumped overboard and some even held their breaths until they fainted.