Baserunning.....1st and 3rd situation

[illiniwek8]

The runner takes off prior to pitcher delivering pitch with hopes of drawing a throw so runner can score.....pitcher is in set position....does not step off...basically does nothing...runner reaches second base prior to pitch....pitcher delivers pitch and it is fouled off by batter...........does the runner have to go back to first? has he established second as his last base occupied prior to the pitch? what is the call here? thanks!