Divorced and moving out.....still hopeful

[NewB3]

Drop off of S4 went horrible this evening. He was excited from noon until we left to see his mom. Since she had a tough time with him last week I took it upon myself on the way over to remind him to be kind dues he was told and make sure he gave hugs and kisses when he saw her today. He took some toys with him and was very nice on the way over. When we arrived he went to the door with some of his toys as he did not want me to talk to his mommy. When he came back to the car I had almost everything out and sitting ready for him, however, he got into the car and said he did not want to stay he wanted to go home with me.
I locked the car doors and took everything up to the door and she open the door. She welcomed me and asked how everything was and was very kind. I laid everything of his on the couch and explained that he was not so great this weekend as he has problems with not liking authority he continuously will ask a question if he does not get the answer he wants. I'm sure she gives in and she probably feels guilty about this whole situation. But then again that would be mind reading.
She came to the car and asked me what I was going to do I took my jacket off and put it in the car and she said rather than both of us stand here I will go ahead and go inside. I said nothing to her and told him if he did not get out of the car that there will be no surprises this week when he came to visit. I then said I will count to three and you need to go inside. With a you can't catch me, he ran out of the car and to the front door. I went to the front door he opened it and said I'm going to close it so you can't come in as he went to close it I walk to the car. I got into the car locked the doors and rolled up the window. He went inside so I thought. As I started the car he came outside. I told him I was leaving and that he needed to go in the house. I started the car and he started to walk back his mother came out looked at me and said I thought you were still here I didn't know you were leaving. I told her that he had already made it inside was going to slam the door in my face so I was leaving. Without saying much she walked back towards the door and motioned him on. Before he can get to the front door and before she could check where I was I was out of the driveway and leaving.
I was really indifferent to the whole situation, it was simply a troublesome drop off. I need to have no conversations with her or discuss anything with her of any importance. I hope it sits well with her.
Again going want to get feeling here but I hope doing what I am is the correct thing. Not sure how to show her I've completely let go other than to be kind, do my parental duty, and leave it at that.