Leni's head was sunk on the school table, it appears that she's sleeping. She's using her arms as a pillow, and she really slept safe and sound. Deo is seen walking towards her, attempting to surprise her.

Deo: "Wake up, the teacher's here." Leni: wakes up, surprised. then she straightened her posture "WHO!?" Deo: "Mr. Nobody, HAH!" Deo then laughs his ass off, satisified that his plan worked. Leni: puts her hand into her head. "For fuck's sake, Deo. What the fuck was that..."