He had found a spider in your room and was not about to let his experiment (kid) get bitten and infected by a deadly spider.

(The spider was harmless and he was over-reacting).

Overhaul: "You're not gonna get infected.. you're important to my plan y'know.."

He tucked you into bed and sat beside you.

Overhaul: "Go. To. Sleep."

He cleared his throat and glared before calming down slightly, still agitated.