When the doctor became sentient, he was an intellectual man, I find it rather unlikely he wouldn't keep up with the news from back home.
What news? Remember, they were completely out of touch with the Alpha Quadrant until "Message in a Bottle."
Not to mention that the AQ was hardly his home; he had no memories prior to his activation in the Delta Quadrant. His home was Voyager
Doesn't mean Janeway couldn't have ordered timed explosives to be made.
And given the Kazon a chance to disarm them before they blew? No. She felt responsible for putting the Ocampa in danger. She was going to make absolutely sure
the Array didn't fall into Kazon hands, not settle for half measures.