"I looked up and saw all this glass shattering. I just thought, 'I've got to protect my son, and covered him as best I could'."
After the glass from the 6ft by 2ft pane had fallen around them, Mrs Mander pulled her young son into a nearby shop and checked him for injuries.
Luckily, neither mother or son were injured in the incident at 2.30pm on Saturday at the Rivergate Centre shopping arcade in Peterborough city centre.
Mrs Mander said: "Ryan was fine just very shaken. But we were both very lucky we weren't hurt.
"He suffers from asthma and could have had an attack. He just went very quiet and didn't leave my side afterwards.
"I have since had a job getting him into other shopping centres because he is afraid one of the panes of glass would fall on him there, too."
She added: "A security guard saw it happen but just walked off. Then a cleaner arrived to clear up the mess.
"I never got an apology. I expect to be able to go into a shopping centre with my son and feel safe.
"I said I wanted to complain and left my name and address so the manager could contact me, but I haven't heard a word."
However, Mike Rogers, centre manager, said both he and the security guard spoke to Mrs Mander and asked if she and Ryan were OK.
He said: "I apologised to her at the time. And I will be writing to her.
"The security guard was present but in a different part of the mall, when he heard the noise he went and checked that she was OK.
"I attended within a couple of moments."
Mr Rogers added: "There is no danger of any of the other panes of glass falling.
"We assume something fell onto the roof, but we've no idea what.
"At least that's one possibility - we don't know what happened."