I already posted what I thought about Shiv's first punch (wrong), his first instinct to have jugia charged with assaulting an officer (OTT), and pounding on a drunk dude (in poor taste and inappropriate). As for today, he should not have apologized. I think on the whole Shiv's character was diminished through these incidents.
All that said, let me revisit... (old habits die hard, I used to work with police officers once upon a lifetime). Shiv is the type that gets hyper at injustice...be it a young girl being denied bangles because she is "widowed" or a sabziwala being threatened by a drunk brat. So, he intervened and overreacted when Jugia started misbehaving with him as well. Overcharging is common and a lot of charges are later dropped when cooler heads prevail. That is what happened here... as Shiv cooled, he decided to cut Jugia a break and drop the assaulting officer charge as it was not reasonable in the first place and he was acting in capacity of aam nagrik not Collector. His taking his laptop to Anandi etc was not inappropriate as it was during his own personal time prior to his work meetings. He had no immediacy or obligation to help out the rude drunk out of jail - its not part of his job as Collector. His work and personal life took precedent over the misbehaving sharabi, I don't see the wrong in that. When you are in pressure cooker job like Shiv, you learn to PRIORITIZE.
Coming to the apology today - its about use of discretion. He wouldn't have left Jugia in jail overnight if he had known he was the Singh's pota for a very good reason. Because his concern and police concern was this guy was drunk and disorderly...he would create trouble if not detained. But, knowing who he is would have given Shiv an alternate option - calling his family and having them keep Jugia from troubling others. Looking at it from this light, Shiv's statement that he would have acted differently had he known is not hypocritical. But, unfortunately such nuance was not shown in the scene.