It was completely safe only when you know how to fix the regulator. because the basic steps that should follow when fixing a regulator are checking whether the regulator is off or not. next, check whether gas smelling is coming or not.
after picking out the regulator and plugging it into a new cylinder check whether it was perfectly locked or not. next, turn on the regulator and check whether the gas smell is coming or not. if any smell is not coming then it regulator is perfectly fixed.
if the above steps are correctly followed then it will be completely safe.