Under the sidewalk is before the gas meter.
I wonder what was the name of the company doing the drilling work.
Private contractors usually do not work on the gas lines before the meter… not without permission and approval from the gas utility company/city., and not without knowing where the gas lines are located exactly.
Private contractors usually do not drill into sidewalks… that is not private property, that too would require permission and approval
Real plumbers have access to machines that can sniff gas leaks… even the apprentices or idiots can put some soapy water on the location to see where it bubbles.
This reeks of a FF.