i was just guessing at numbers and figures

Eurus taunts him and she tells him what he should have realized. Molly was never in danger. Eurus knows what’s important to him. Eurus wants to hurt him as much as she can. All those little emotions—Eurus and Molly set them free. Eurus lit the spark, made Molly say them, but Molly made him realize something he can’t bring himself to contemplate.

Emotions are his downfall.