"It was part of Pat's initiative for the community," she said. She'd done some artwork for him when needed, and found the enthusiasm of the campaigner, his commitment to Napier and to the Pilot City Trust through which the calls for social change have often been pushed difficult to resist.
In a way which will be familiar to the way people have taken to Magill's purpose of the years, she said: "I only did it because Pat asked."
Magill had also enlisted the schools of Napier, to get pupils to do their own art impressions of Napier and its issues.
Cook, who had up to about three years earlier been a tutor at the EIT, enlisted EIT students "Nathan, Bernard and Shaun" to help in about a month of bringing new colour and meaning to an otherwise staid, grey wall of concrete blocks.
"It was like a quilt, with the hands at the end sewing it together," she said. "It was like a response to what was represented by the holding cells behind it."
Magill said: "The reason I asked the police was to bring back a relationship between the community and the police."
The mural carried messages from the children and the artists, such as "Bullying must be stopped", "Without a sense of caring there can be no community", and "can we forget the prejudice formed by society".
Now on a mission to have Napier dedicated as a "Child Friendly City", he said: "We were going to do it up, but then we were told the wall was coming down. We will do another one."