Do audit firms dismiss trainees?

dear friends, iam a ca final student. I have completed my articleship. Right now i have joined a big ca firm as a trainee since i had very poor exposure in articleship. During my interview i had openly told the partner that my exposure is low and i have come to learn the work. My fear is that if i make mistakes during my work even after my sincere efforts, is there a possibility of me getting thrown out of job, since there is no protection like in articleship. Please clarify for me.