Winning / Losing your placement matches has little effect on your placement SR, you can lose all 10 but play like an absolute monster and get a high rank.
You won't always get paired with other people doing placements, you will also get games with and vs people who have already finished theirs but your MMR matches their current SR, so there is little difference if you place now or wait.
I smashed out 10 in a row last night on my 2nd account I'm only playing tanks on and got a decent placement with a 6w-4l result. Ran into an annoying Torb only player twice, but meh, it happens, blocked and got on with the game.
You won't always get paired with other people doing placements, you will also get games with and vs people who have already finished theirs but your MMR matches their current SR, so there is little difference if you place now or wait.
I smashed out 10 in a row last night on my 2nd account I'm only playing tanks on and got a decent placement with a 6w-4l result. Ran into an annoying Torb only player twice, but meh, it happens, blocked and got on with the game.