The killer couldn't spot or predict Crystal's move. Her outstanding performance on the battlefield puzzled the killer that he was left in a haze for a while. It gave him a hard time to fight back against Crystal's newly developed combat skills.
She felt proud of her body for stretching inhumanly. What's why she was able to fight back this killer? But all her skills were enough to kill the killer, and he returned to attack her again. Crystal got confused.
She assumed the killer to be a great warrior or a master, because the amount of strength he had to fight back wasn't ordinary. Normal enemies would back down or be killed after fighting for this long, but this one didn't seem to be exhausted by fighting and using so much of energy would have depleted to make the person turned into ashes.