The earlier the better

In the middle of the night, Alita woke up with a start when she heard a slight disturbance. Panic hit her when she looked beside her and didn't find Axel there. Earlier, she had fallen asleep beside him after he assured her that nothing would happen and they wouldn't be attacked. 

Where could he be? She strained her ears to know if he was in the bathroom. As she tried concentrating, the door to the bedroom flew open, startling her. 

She only relaxed when she saw it was the person she was looking for. Her mind was already calculating how she would fight off any strange vampire that comes to attack her.

"Are you okay?" Axel questioned, noticing how her heartbeat spiked when he entered the room and seeing how alert she looked. He had not expected her to be awake as she had been sleeping soundly when he left the room. Could she have heard the noise?