Ex-CIA officer David Rush’s alleged years-long scheme that netted him $40 million in gold bars and a top-secret security clearance has those in the Clandestine Service community questioning how he slipped through the fastidious vetting process — and who else may be flying under the radar. Former CIA staff operations officer Tracy Walder was baffled over the stunning allegations against Rush and believes they could point to a much more troubling issue within the agency. “This would have been a