To dream of a grenade represents suppressed emotions or issues in your life that are about to explode. You may feel cheated, limited, or prevented from doing something or expressing yourself in some way.
To dream of grenades that don’t go off symbolizes a situation where unexpected events or factors are making that situation less important than you expected.
To be killed or injured by a grenade symbolizes you or some aspect of your personality that has become overwhelmed by suppressed emotions or situations. You can’t contain or restrain yourself any longer. It may also reflect someone else that finally let loose on you.