The schools I'm at might be different but in my experience the student evals aren't the deciding factor in employment. They are important and I was once talked

The schools I'm at might be different but in my experience the student evals aren't the deciding factor in employment. They are important and I was once talked to because of a poor student eval (although in that same meeting she said she wanted me to help out in course instructor meetings since I had taught the class several times and wanted me to mentor the new grads. It was a confusing meeting...) and I saw a fellow grad student come under a lot of scrutiny for some odd teaching (I really think the guy was bipolar) but there was never any fear that you wouldn't be able to teach next year. I'm currently an adjunct at another school and luckily my evals have been quite positive overall so I haven't had to worry about it here.