Answer:
Mr. Tumnus was supposed to turn Lucy over to the White Wich but could not bring himself to do this.
Step-by-step explanation:
Due to his tender and kind personality, Mr. Tumnus is amazed at the human personality (although this is the first human he sees).
Therefore, it can be said that Mr. Tumnus appreciates and sticks to Lucy Pevensie enough to help her escape the land of Narnia before the witch arrives.