Mayor Bill de Blasio on Thursday skipped an NYPD swearing-in ceremony made somber by this week s assassination of a cop   then hours later revealed he was busy preparing to jet off on a surprise trip to join leftist protesters at the G-20 summit in Germany.Hizzoner s overseas jaunt was kept under wraps until just 90 minutes before he took off from Newark Airport. A last-minute announcement said he  will attend several events surrounding the G-20 Summit, including Saturday s Hamburg Zeigt Haltung rally. De Blasio will be the keynote speaker, organizers of the demonstration   Hamburg Shows Attitude   tweeted. The mayor also made sure the free trip will include a visit with his son, Dante, a Yale University student who s spending the summer on an internship in Berlin, a City Hall spokesman said.Presumptive Republican challenger Nicole Malliotakis accused de Blasio of abandoning pressing issues in the Big Apple to pursue his progressive agenda in Europe. Unbelievable. Instead of jet-setting around the world, he should be here doing his job,  said the Staten Island assemblywoman.  A police officer was murdered, street homelessness has skyrocketed and people continue to get delayed on the trains. Malliotakis   who later tweeted a doctored image showing de Blasio in an Alpine hat and lederhosen, grinning behind a plate of bratwurst, wienerschnitzel and Pilsner glasses   also blasted him for blowing off the NYPD ceremony at the Police Academy in Queens.Malliotakis jabs de Blasio with Photoshopped tweet over Germany trip https://t.co/DtTRaAQBXD via @nypmetro  carl campanile (@ccampy) July 7, 2017 The mayor should be embarrassed by the way he has treated the men and women of our police department,  she said.He is off gallivanting & I'm here pointing out problems w/ garbage collection, the most basic of city services  https://t.co/yW4MZ02u3O  Nicole Malliotakis (@NMalliotakis) July 7, 2017New Jersey Transit tweeted about a schedule change after a train was derailed yesterday while entering Penn Station in NYC, causing delays in transit for commuters:All Midtown DIRECT trains are being diverted into Hoboken Terminal. NJT is cross-honoring w/ PATH, & NJ TRANSIT & Private bus carriers.  NJ TRANSIT (@NJTRANSIT) July 7, 2017GOP Mayoral candidate Nicole Malliotakis retweeted NJ Transit s message to keep New Yorker s apprised of the change, in the absence of the protesting NYC Mayor DeBlasio:I'm retweeting this to keep #NYC residents informed since our mayor is in Germany where it is 4:57a.m. https://t.co/qV1nXSGHHM  Nicole Malliotakis (@NMalliotakis) July 7, 2017I m so old, I remember when mayors stayed in their city to do their job rather than try to make themselves ideological symbols. https://t.co/deDbXzWU3g  John Avlon (@JohnAvlon) July 7, 2017The head of the NYPD sergeants union also attacked de Blasio. As the city mourns, its leader flees,  Ed Mullins said.  And then he wonders why he has a problem with the police. A real leader stays with the city in this time of hardship. NYP