Already, this new NBC series, which premiered Monday, is awash in symbolism and irony. Its premiere, opposite the second episode of CBS’s summer hit Under the Dome, drew only an estimated 3.2 million viewers. Both new series are scripted shows about a suddenly isolated group of people – a small town in Dome, contestants in a reality show in Siberia (actually filmed on location in Manitoba, Canada). Dome, by Stephen King, grabbed viewers immediately. Siberia, scheduled against it, not