Street racing is dumb. Tunnels can be dangerous. So it stands to reason that street racing in a tunnel is so dumb that nobody will ever try it. Guess what? There are people that dumb.
We're not sure what exactly started this race/chase. Was it an actual race? Were the drivers mad at each other? Was there a sale at the local Coconut's Records?
We'll probably never know.
(Hat Tip to Automatch!)