As a former nursing instructor & CNA instructor, I agree with everyone above. Put it on vibrate, check messages at break, etc. And kids often call for things they think are "emergencies", but...
Most grad schools require a B or B+ average. NP & CRNA programs are very competitive. The higher your grades, the better. Get that RN first, then some experience before you start worrying about...
It is the responsibiloity of every employee to know what to do if they are injured. I am sure there is a procedure for what to do when you are injured (osha IS EVERYWHERE). It is up to the supervisor...