This question seems to imply that Bana and his two friends are deliberately opting for execution in order to try and highlight the corruption that exists in African society with the hope of changing it. Upon close examination of the story, however, it appears that this is not the case. Bana has no real hope that his death will change society, and seems to be more relieved than anything else to be dying. Note how in the following quotation he describes himself and the similarities with those in the stadium, watching his death:
The divide between us breathing like everyone else in the Stadium and us as meat for worms is, oh, so slim, it makes life a walking death! But I should be glad to be rid of the world, of a meaningless existence that grows more dreary by the day.
Bana is very aware that his state does not actually separate him at all from those around him, as both he and the spectators are all "meat for worms," and there is very little difference between them. He goes on to express his weariness of life and the world, describing his existence as "meaningless" that only becomes more and more "dreary" with each passing day. Bana does not present himself as some sort of crusader, therefore, who hopes that his sacrifice will result in lasting change. He presents himself as somebody who is worldweary, and believes that the corruption in African society is so endemic that change is impossible. This of course greatly adds to the message of the piece: it highlights the extent of Africa's problems by not offering possibility of change.