Basically, the reactors and supporting systems aren't in any way properly shielded, so they're throwing out a lot of wide spectrum interference. If you can take out the reactors, the ship loses power (so can't maneuver / raise shields), and that interference then drops off. That's assuming they don't detonate, in which case the interference goes immediately, probably along with a good quarter or more of the ship :)<br/><br/>I should have previously been saying reactors for power generation, rather than engines. That was poor wording on my part.<br/><br/>Engines drive the ship forward, reactors power them.