Sitting at a concrete table in the amusement park, 15-year-old Aisha — not her real name — says she was the only one of her family to survive when Boko Haram invaded her village in 2015.
When her parents refused to let her marry a Boko Haram fighter, the militants shot her father "on the spot" and tossed her mother into a makeshift prison full of urine and faeces.
Days later and starving, she finally let her daughter go.
"He forced himself on me," Aisha said of her new husband with whom she lived in Sambisa Forest, Boko Haram's stronghold in Borno state.
"He would bring bombs and tell me to pour water on them, so they didn't explode."
Wearing a white hijab with two ruby studs in her nose and a wary look in her eyes, Aisha says she saw militants strapping explosives to young girls and boys.
The rebels gave them 50,000 naira ($158, 145 euros) for their families and told them they would go to heaven. If they refused to blow themselves up, they would be shot, she said.
In December, the Nigerian military invaded Sambisa Forest and rescued Aisha. She now lives with a man from her village in an IDP camp in Maiduguri.
But she isn't going to school. Asked what she wants to do in the future, she doesn't seem to know.
"Clothes make me happy," she eventually replies.
Schools were only officially reopened in Maiduguri and accessible areas of Borno state late last year after closing down in 2014.
Hundreds of others across the state are waiting to be rebuilt after being destroyed by Boko Haram.
To address the orphan crisis, Shettima's goal is to build "20 mega-schools across the state". His government has also floated plans to build a massive orphanage for 8,000 children.
Whether construction begins depends on how much the Borno government receives from the federal government, a notoriously unreliable benefactor.
It is also counting on the generosity and courage of international donors.
"The destruction of schools, the displacement and loss of school years, and the abduction of school children has reduced the level of access to education in a safe environment," said Oge Chukwudozie, manager of humanitarian organisation Plan International Nigeria.
"Given that the crisis directly targeted schools, non-government organisations had to play it safe so that children will not be exposed to direct attack by Boko Haram."
Nigeria's government is unlikely to resolve the school shortage quickly. But without urgent intervention, the risk of renewed violence increases.
"They need a second chance at life," said UNICEF's Manyok.
"Otherwise they become a destabilising factor. It's just a time bomb."