director andrew davis reworks his fugitive formula and the results are about as exciting as his last film-- the dreadful comedy steal big , steal little-- was funny . 
keanu " i'd rather play music than play another action hero " reeves is the grad student on the run , who , along with his superfluous sidekick ( rachel weisz ) , has been framed for a sabotaged science experiment that vaporized eight chicago city blocks . 
 ( the mushroom-cloud explosion is a knock-out and easily the best part of the movie . 
or , as one audience member succinctly summed it up : " whoa . " ) 
false information implicates their involvement and boy and girl are soon on the run , fleeing over open drawbridges , across icy lakes , and through the corridors of power at a top-secret , underground energy facility . 
aiding and abetting is the team's shady mentor , played in an excellent-but-so- what performance by morgan freeman . 
 ( brit brian cox is also about , as the behind-the-scenes bad guy . 
he has some fun fiddling with a southern accent . ) 
unfunny , overscored , and without a single shred of suspense , chain reaction is * the * summer movie to walk out on . 
if you make it to the end , a mess of cross-cutting involving another imminent explosion , you'll hear somebody say " i guess it's time to go . " 
heed that warning .