Station Agent reported that a male patron exited through the emergency gate of the Castro Valley Station, without processing a ticket. The agent reported the male was also intoxicated. An Officer contacted the male and determined he was too intoxicated to care for himself. The male had a valid ticket, but failed to process his ticket out. Subject was placed under arrest for public intoxication and transported to Santa Rita jail for booking. A Sergeant attempted to debrief the subject, but he was too intoxicated to interview.