Once, Alphys got the scare of her life. She came home late, having had to stay at the school late for a staff meeting in her department. Since Undyne's department wasn't involved, Alphys expected to come home to Undyne already home, either at the couch or in the basement working out.
Instead, she came home to silence.
Terror filled her, her mind automatically going to the worst scenario - made even worse by the fact that Undyne's coat, boots, and bag were nowhere to be found.
Undyne had finally left her.
Alphys stood in the doorway, frozen in place, trembling, her mind desperately going over what she had done to make Undyne leave her. She started to cry; she could think of nothing, absolutely nothing, that she could have done.
When the door opened behind her, she jumped back and dropped her bag. Undyne stood in the doorway, holding take-out. "Hey, Alphy! I knew you had to work late, so I-ack!"
Alphys clung onto her tight, burying her wet face into Undyne's shoulder and not letting go. Undyne stumbled, almost dropping the food. "Alphy?" she said, confused. "Are... you okay?"
"Y-yes," she murmured. It was true. "Y-you're here. I-I-I'm okay."
"Of course I'm here, nerd!" Undyne smiled. "Where else would I be?" She gave Alphys a hug, then added, "Come on, I'm starving!"
Alphys didn't let go for a moment, calming herself, before finally letting go. Making sure Undyne didn't see her tears, she asked, "What did you get?"
Undyne grinned proudly. "Noodles. The best!"
Alphys smiled in return, her heart warm again. "I agree," she said, meaning so much more.