Regards him not being off duty, if an officer was not on shift and saw something happen, but he negated to do anything about it then he would be in bother. If an officer has his warrent card on him, he must do what he should do.

I seriously doubt an officer would be working at tescos as a second job. Days officers don't work on shift are calledrest days. Normally are often warned to come to court to give evidence on these days. A job at tescos would heavily interfere with this duty.

Plus pay at tescos is wank, three days at tescos would earn as much as one days overtime in the police station I imagine.