The Bombardiers, when on a void subclass, suppress targets hit by the bomb. This is not proccing echo of domineering, which is supposed to reload equipped weapon and give mobility on suppress. In the clip, the suppressing grenade procs both stylish execution and domineering, while bombardiers procs neither. If the target survives the initial blast and then is killed, bombardiers will cause stylish execution to proc, but never causes domineering to proc.