Not really a solution, more of a suggestion for those who don't/can't boost:
- Grab the stickies from the top of either building near the explosive barrels and head down into the underground tunnels. Use the shield doors to your advantage, popping through to stick then dive back. Just watch out for people with maulers down there.
Alternatively, play crazy king. You'd be surprised how many people stand still facing away from you ;-)