There are a few problems with how you played it. An opening salvager is a risk in shelters kingdoms that have a key cards at 5 coins, such as the laboratory.
He has to take this risk. Well, more specifically, he has to open with Salvager to pare down his deck ASAP, and Salvager/Silver still hits $5 rather frequently.
Death Cart is a mistake. There's already strong drawing with KC/Lab, and it's very easy to pair up Salvager and/or Expand with MS to gain lots of Gold quickly and use them.
EDIT: I think the biggest problem that the engine has to contend with is that the rush can pile out slightly more quickly on IW, Gardens, and Ruins by gaining Death Carts and also score more points in the process. I tried the rush and got 40 VP in
14-15 turns while the engine can score >40 VP on
turn 14 with fair luck. But unless someone can shave the engine down to 13 turns consistently, I'd probably prefer rush in a vacuum.
(Disclaimer: I've gotten quite a bit worse at Dominion.)