While many of those who were in the evacuation houses were weak with more or less Level 10 as the above average level, most people knew how to fight and how to strategize, thanks to Alterra's training requirements.
They also grouped together with their own shields (though these were mostly Class E bone or wood equipment) and mobbed enemies together.
Fortunately, all the enemy powerhouses past level 25 were ambitious and wanted the Lord Token, so they wouldn't bother with useless massacres, probably thinking they could do that as they wanted once they got the token.
There were also Alterrans who were level 10 and therefore awakened, and used their skills whenever they could against their enemies.
While their elements were small, tiny, and untrained, they could still chip away enemy's defenses as long as they hit them often enough—and showering enemies with little embers, tiny wind blades, and so on was something they were more than happy to do.