I saw the tweet Cohen wrote back to Tom. He pretty much said he only noticed him when Tom came up to him and asked if he would do a selfie with him. Cohen also said he had no plans to be with Tom. So it was really weird when Tom lied and said he was going to be with Cohen all weekend.
I think Cohen's tweet disclaimer about Tom came out during the interview. Maybe someone talked to him in his ear and told him Cohen basically outed Tom as a stranger and wouldn't have had anything to do with Tom if Tom hadn't asked for the selfie.
It's possible Tom froze because in the middle of the interview he realized all he said about being with Cohen all weekend was a lie and his audience would now know what a liar he is and none of the stuff he was saying about Trump was the truth.