Goofs

It is also virtually impossible to stay alive inside the gas transmission pipeline without some sort of a protection vehicle as the pressure inside is many times (up to a 100 times) the atmospheric pressure. A human would be just crushed by such pressure. There is no way one could just 'open a hatch' and step inside.

It is impossible to move inside a gas pipeline without the pipeline operator immediately noticing it, since the pressure in the pipeline is monitored in minute detail 24/7.

The trains used in the channel tunnel are driven electrically (the current collector on top of the locomotive is clearly visible). Yet, in all exterior shots of the train moving before entering the tunnel, no electric lines are visible.

Due to Operating and Environmental reasons, there are sensors that monitor pressure and flow rate continuously on all cross-country piping and the first time there was a minute pressure drop in a pipeline of that size, it would immediately shut down the pipeline.

After about an hour the relief helicopter lands outside the tunnel next to the track. There is a 'fish-plate' visible joining the lengths of track together. This has not been the desired way to join track together for many years and certainly not on a high speed, state-of-the-art rail network.

If one would pause at precisely 18:18, one can see the the holes drilled into the divots of the cement/statuary into which the squibs were drilled and packed.

Multiple times somebody is lying on the roof of the train, hiding or shooting. It is quite possible that that person would have been killed by electrocution due to a flashover from the electric overhead line.