@ThunderaMaou you're angry about the wrong ingredient, she brought the bread from home, it's the pastrami that was sourced locally, and they eat because they feel like it, they don't need to.
Te clocktower's battery, or capacitor, had a port that was compatible with the charger, but it likely wasn't it's main source of power, just a backup, just like if you tear open your phone you can probably still find things that are obsolete in there, that have just not been implemented, or removed. Besides, that's the charger for some eccentric proffessor's old tablet, that his robotic servants are keeping out of nostalgia. It's entirely possible that that tablet was terribly out-dated before Suoh was put to sleep.