A husband and wife pulled a so-called joyrider from a stolen car he was struggling to control close to their Belfast home, the High Court heard.
The couple detained the 17-year-old accused amid suspicions he was high on drugs and threatening to return to "sort them out", prosecutors claimed.
Praising the action taken by them in the middle of the night, a judge said: "They came forward at great risk to themselves."
The youth, who cannot be identified, is currently charged with taking a motor vehicle without authority, theft, handling stolen goods, disorderly behaviour, assault on police and a number of motoring offences.
During a bail application Crown lawyer Mark Farrell said the husband and wife saw a Chevrolet car "joyriding" on Henderson Court at around 5am on May 8.
They described the vehicle as going into hedging as if it was not under control and feared someone could get hurt if action wasn't taken, the court heard.
According to Mr Farrell the couple left their home, approached the car stolen from another address, removed the driver and held him on the ground until police arrived.
"He made threats during this period, saying 'I know where you live, it would only take two minutes to sort you out'," counsel alleged.
PSNI officers discovered the teenager being restrained, slurring his words and claiming to have taken prescription drugs known as "buds".
During attempts to handcuff him he allegedly struggled, shouted obscenities and punched a constable, breaking his glasses.
Opposing bail, Mr Farrell cited police concerns for public safety and car crime in the city.
Reference was made to an unrelated incident in April when young mother Lisa Gow was knocked down and killed by another man driving a stolen car in north Belfast.
Defence barrister Conor Maguire accepted his client has past issues with substance abuse, but insisted there was no evidence he would try to interfere with the witnesses.
Mr Maguire also told the court the accused will be transferred from juvenile justice facilities to Hydebank Young Offenders' Centre once he turns 18 in the near future.
"There's more of a likelihood he will engage with older, more hardened criminals," the lawyer contended.
"He fears that not only will be unable to address his addiction issues, but that they will be compounded."
But adjourning the application, Mr Justice Maguire said the consequences from the alleged incident could have been "absolutely horrendous" for members of the public.
He added: "What would worry me is if he has time on his hands, takes drugs, takes a car and there's a fatality or something of that nature."