If he had Carmine's expert opinion by his side, guiding him about the pitfalls and traps of the Remedium and the capabilities and weaknesses of Canzers, he wouldn't even have to fight at all.
He could simply use their weaknesses against them and sneak past into the Church and onto the basement where the Ifrit was located.
That was the mission. It was about making sure the Door remained safe, it was not about fighting Specialist Canzers.
He had no chance of ever killing them anyway. He didn't have enough strength to do so, even with his full use of his LifeSkills and mutations. His most powerful LifeSkill right now was the 1st stage Pre-Intern realm Bloodline Transformation, and that was still two realms below the Specialist-realm. He had no chance.
