> The Swiss machine in the
    > video did 400m in 4 months.

No, a lot of the time the machine was stationary because the needed to manually reinforce what they were about to drill through, so the machine wouldn't get trapped and buried in gravel. Wouldn't Prufrock-3 be similarly slowed down!

In addition to that I assume that the 7 miles a day claim assumes 24/7 drilling, whereas I wouldn't be surprised if the swiss were doing 8/5 drilling.