You can play it on any gamemode you want. lets do it on Freeforall.

1. Get infected with someone with the mod - go to an infected lobby

2. Make a xbox party and one on MW2 game, go to private game infect everybody.

3. Everybody is infected. You need to be Same players who is in the party and in the private game.

4. When everybody is in the Xbox live party and infected leave the game and go to main menu.

5. Then the host leader or someone else in the party search for a free for all game and everybody Join his session in progress fast as possible.

6. If everybody Joined the game, you have the superspeed online with XP:)
(if you didnt join, get infected again and try again)
7. It's pretty easy!

8. Have fun!

have fun