I'm not sure if the Timbers really could have scored 10 goals, but they produced one of the more lopsided ties in recent history.
Below is a chart of the largest single-game Expected Goal Differentials (xGD) over the past two seasons.
Portland's 2.17 edge in Expected Goals ranks 13th in the past 575 games, and third among games ending in a draw. A positive xGD during the 40 minutes played at an even gamestate also suggests that Portland didn't wait for a deficit to turn on the jets--a good sign for a team that has allowed itself to get blitzed early week in and week out.
The average actual goal differential on this list is almost two full goals per game, so it's not any great stretch to say that Portland will see better results if it can continue to produce better xGD results. However, that's a tall order for a team that is still ranked third-to-last in even gamestate xGD.