Get pre-approval. Is that what your boss requires?
If they don't approve it, just alter your work habits so you have time to do the charting that will cover you in case of trouble. You have to protect
yourself. Do all that is required of you, just don't do work that someone else can do. If the pt has to wait, it's not your fault. Emergencies are, of
course, the exception to this. Don't let a pt be harmed ever, if you can prevent that.
That's what I learned to do - cover your fanny. If it meant someone else had to get the pt a blanket, so be it.
Our techs would always hide out as soon as their relief arrived. They conveniently forgot that their shift ended 30 minutes later, not the moment
their relief appeared. I refused to do their late Rounds (other nurses did, which made it hard for me not to, but I stood my ground. Why should I
do their work?) or answer lights that last half hour because I had to count, give Report, do my end-of-shift Round, finish charting, etc.
I figured they could damn well answer lights and make their own last Round, not go into the locker room or stand by the clockout clock for 1/2 hour.
Do not work off the clock. If you get hurt or make an error, Worker's Comp and the employer's coverage might not cover you.