Complex sentence: V-Man, who's encased in a protective suit, stays behind as per the plan; after the other heroes are gone, he tears off his outer suit and lets his virus destroy all the F-Troops.
Split into simpler sentences: V-Man, who has encased in a protective suit, stays behind as per the plan. After the other heroes are gone, he tears off his outer suit and lets his virus destroy all the F-Troops.