I've played two rounds of silver now. In the first, we flopped and died on Wave 3. We managed to beat the second. I went down a fair bit, but that happens on Silver, and in my defence I was only level 15.
I've been in a couple of other silver lobbies, but a level 8 should not be playing silver and if I see that I exit immediately. My successful team was 15, 16, and two 17s, and even we struggled.