Unexpected Situation

What do you do when a friends ask you to do something but you have not asked your parents for permission to go there?

For me it is very important to have the permission of my parents.

I ASK THE PERMISSION OF MY PARENTS TO GO WITH MY FRIENDS AND HAVE NO CONCERN.

UNEXPECTED SITUATION 

I consider an unexpected situation when happens that we have planed, is unexped.

Can happen in any moment.

EXAMPLE THE UNEXPECTED SITUATION IN THE SCHOOL:

An example the unexpected situation is:

When your teacher put a surprise exam.