The most difficult aspect of geth existence for organics to comprehend is that a body is meaningless to geth. The biped form commonly perceived as a geth is nothing more than a "mobile platform." A geth's software -- hundreds of programs whose interactions mimic organic consciousness -- can be installed in any given hardware. The geth that was a bipedal soldier an hour ago may now be a quadruped heavy armature and, in another hour, might be a starship. Between tasks, geth programs upload to gigantic space station mainframes that allow billions of programs to exchange thoughts and memories with minimal lag.
The claim that the geth are an example of the extreme risk posed by AI development is misleading. As opposed to the "top down" design of organic-created AIs, in which hardware and software are specifically designed to achieve consciousness, geth are a "bottom up" model. They were never intended to possess more than animal-level, trainable reasoning.
Designed as VI-driven robots -- not significantly different from modern security mechs -- geth consciousness developed as their adaptive learning programs interacted with one another via networked processing. The geth code-base discovered that three individual robots using a wireless local network to form a single mind could perform many tasks more efficiently than they could as individuals. As these local networks were more heavily exploited, they reached a critical mass of processing, achieving consciousness.
Modern geth retain this remarkable interconnectivity, constantly exchanging data with one another and networking to increase their cognitive abilities. To geth, these mind-sharing abilities are as natural and unconscious as breathing is to most organics.