The SEWIP is a combination of defensive weaponry and requires a large power source. It has reception antennaes and controls chaff launchers and jams radar . It even has it's own manned control center (Slick-32)
The base of the SEWIP contains some high voltage cables, along with signal carrying cables. When this was ripped loose from the ship, it could have caused a major electrical failure, and partial/complete communications failure.
So... hitting it in the antennae (SEWIP) might have taken out the communications.