I don't want to laugh at an ostensibly serious situation, but I think bombs usually hurt people a bit more than that.
The "bomber" is obviously deranged or has the mental age of a child if he thought his "bomb" would do any damage. Burnt his hands and made people's ears ring.
You can hardly call it a bomb, nor an explosion. FFS, a Bic cigarette lighter would cause more damage if it exploded.