How are we to read verse 19? Do we lean entirely on the easy interpretation, "What God wants, God gets"? Is that what "the Lord was with him and let none of his words fall to the ground" means?
Or, should we be influenced by the context of this memory? Eli heard the hard word from God transmitted through the young Samuel. And Eli accepted the word. "Don't hide anything from me," he commanded Samuel. So Samuel did what Eli was willing to have done.
What would have happened to God's word if Eli had told Samuel to be quiet, quit running into his room, and go back to sleep?
Can you imagine being Eli?