I was unable to get out… Since then, I have been afraid… For IELTS practice I would strongly recommend taking even just a couple of lessons with an IELTS specialist teacher, such as myself. I have helped thousands of students achieve the score they want in both the General and Academic IELTS examination: www.italki.com/en/teacher/2539925

'20 mintes from school' normally means that it takes 20 minutes to get to school, by whatever means of transportation you are talking about. However, 'I have to rush' makes it sound like that have to be at school in 20 minutes. They could be using the phrase in an unusual way.