Guardians are not equal to Spartans. The only real advantages they have over Spartans are their super abilities and their ghost reviving them. But Spartans are better trained and have a knack of taking on the hardest odds and succeeding quickly. They could easily take the guardians fast and kill the ghost as it tried to revive or the guardians can drop a super but need time to charge. Time Spartans can take away. [spoiler]just realized you said Spartan 4 and yes they quite possibly are but still they are even better trained [/spoiler]