This can be achieved alone in a private Plant the Bomb match. Make sure to set the game Private so no one is able to join. You should also set the Team Balancing off under Room Settings, and then choose to be on the Warface team and start the match. Now, you will have 5 rounds to defend the bomb for 3 minutes each time, simply kill yourself with a grenade in each of the round 5 rounds. Now on the sixth and final round you should plant the bomb, wait for the one minute counter for it to blow up which will grant you the win.