MC is learning from his mistakes of babying those he cares about too much. You can see on the last page he's really tempted to grab Lillith's hand and reassure her but he holds himself back. He knows how weak he's made Cordelia and doesn't want to repeat that mistake anymore than he has to. It was the entire theme of this chapter.
I always imagine in my mind that when OP characters in-universe fight, do like that, with a fuckton of sealing/debuff skills to make the other fighter useless/average, glad to see actually somebody using that idea