Complex sentence: If they lose, which they do, they will shovel manure for a year on the Paveletskaya-Koltsevaya but Artyom quickly escapes and travels through an unfinished tunnel.
Split into simpler sentences: If they lose, they will shovel manure for a year on the Paveletskaya-Koltsevaya. After losing the bet, Artyom quickly escapes and travels through an unfinished tunnel.