Cutting a live transmission line is incredibly foolish, for many reasons, but I'm guessing the station has a modern(ish) solid state transmitter, which has great foldback protection.

I've seen (and personally tested) AM transmitters dead shorting, and within less than a second (probably less than 100ms, but I haven't measured precisely) it will fold back on a dead short to like 1% of its operating power, lower if it still detects a short.

This is to protect the (even more expensive) transmitter from lightning strikes or other weird eventualities (like the line leaking pressurized nitrogen, used to prevent shorts from moisture mainly).

But replacing that 3" transmission line is not cheap or fast. Usually the runs are planned and designed, and every elbow / connection has losses that are accounted for.