I am just curious why Nord Stream 1 did not erupt in flames? It should have. Flowing nat gas is highly flammable.
First of all, both pipelines contained a substantial volume of pressurized gas. That one had a flow probably made little difference because the flow would have been stopped immediately when the line depressurized, I should hope and presume.
There was no possibility of the gas burning until it escaped into the atmosphere, and apparently there was no source of ignition at the surface.