Here follows one way to get the Dozer tank without wasting too much time for it.
1. You should first reach the Platinum division of the Arena, with a good deck of your one, or build according to advices you will receive from the team.
2. In the arena tab, lets click the refresh button and find a good target. A good target is a deck with Elena and no creatures. So refresh and find it.
3. Launch an attack with your normal attack-deck. If you get Elena with no creatures, that's a quick win. Otherwise, refresh again.
4. Switch to a very quick rush deck. For example, Natasha and Hunter. Switch to speed x4. Set to Auto-mode.
5. Play your favorite music.
6. Now that everything is ready... Quickly click on button "fight" 4 times (or at least several times).
7. Repeat during a few minutes. You should rapidly reach a steaming speed of 50 wins per minutes. At this rate, Dozer should be yours in no time. And voila !!