A boy pulled out a gun while chatting about an armed robbery in a car with his care worker, a misconduct hearing was told.
He told Catrin Davies, 25, he planned to "stash" it while being driven from his Wrexham care home to visit his grandmother in April 2017.
The boy, 15, known as Child A, was arrested on suspicion of being involved in an armed robbery days earlier.
Ms Davies is accused of failing to take timely action by Social Care Wales.
The Mold hearing heard she was "very worried, scared and in shock" and tried to "stay calm, remain as friendly as I could" after the incident.
'Others at risk'
The childcare agency worker described arriving at the home to be told she was to drive Child A to see his relative.
But Ms Davies said she was given no care plan and only knew he had been bailed by police after overhearing a conversation at the home.
She said: "It is hard to believe I was put in the situation... I accept I was naive."
During the car journey, Child A opened his bag, revealed the gun and said he was planning to "stash" it, the hearing heard.
After dropping him off, Ms Davies called the home and said there had been an "incident", but was told to return there and it would be dealt with.
The colleague she spoke to said Ms Davies did not mention the gun until she returned to the home at 23:00 BST, at which point police were called.
Asked why it was not mentioned or she did not consider others could be at risk, Ms Davies added: "I feel I was suffering from shock and mental exhaustion.
"I had not had training to deal with an incident like that."
The fitness to practice hearing continues.