Adomah scored the opening goal for the visitors, who were kept largely quiet by the Iron apart from a period in the first-half after City scored against the run of play.
"I didn't see it originally because I was following the ball and the tackle was so late," said Millen on his club's official website.
"When you see it on the DVD you can see their lad [Togwell] actually stamp on him. It was a naughty one and if the referee or assistant had seen it then he would have been in trouble.
"Albert was a caught a number of times in the game because they weren't able to cope with him. He was a real outlet for us."
Adomah was replaced after the challenge but will be fit to face Watford on Tuesday night.