Criminal profilers have long noted that the Zodiac's behavior at the Lake Berryessa attack on September 27, 1969 represents a significant departure from his pattern at previous crime scenes — and that this departure reveals something specific about his psychological needs. At Blue Rock Springs and Lake Herman Road, he shot victims and left immediately. At Lake Berryessa, he arrived in a costume bearing his own symbol, introduced himself by name — 'I am the Zodiac' — tied up both victims with rope he had prepared in advance, and then spoke to them at length before attacking. Survivor Bryan Hartnell recalled the conversation lasted fifteen to twenty minutes. Analyze: what does this behavioral shift reveal about the evolution of the Zodiac's primary psychological drive between his first attacks and the Lake Berryessa attack, and what risk did this shift introduce that his earlier method avoided?