Doubtful Ryan runs the day to day operations of this PAC - but it is in fact his PAC as reported.
But even if so, the flyer was targeted at liberal / Dem voters to try to demoralize their turnout - reverse psychology move to make them think they really don’t want to turn out and vote for this guy. Articles reporting this as a political trick were reported prior to the election even taking place. This article is from two weeks before the election highlighting this: https://www.washingtonpost.com/news/powerpost/wp/2018/03/01/republican-super-pac-warns-democratic-voters-that-their-candidate-supports-gun-rights/ Whether or not that was effective use of funds is open for debate (I think it is personally a wasted effort that would have been better spent on targeted GOP base voters to show up), but the objective was not to elect Lamb - this same PAC was spending millions on TV ads attacking him.
However, there is no doubt there are elements within the GOP who would love for the party to go down in flames this year to prove a point and the more extreme elements of this faction would use it to create a narrative that Trump must be removed to save the party...and it is a narrative that would in fact have legs should the GOP not only lose, but lose big. That is why the opposite message must be sent with a GOP victory - even for those who may not deserve it to block this narrative from taking hold - hard to argue Trump is destroying the party and “the people” want him removed from office if his party has a decisive victory, but could be easily argued if the opposite ends up occurring - and of course as we know the media would carry that message to build momentum. I was far from a fan of Trump, but many of his accomplishments are conservative and way overdue such as tax reform, and he is appointing some of the best judges ever put on the bench and that must continue, and if he goes down, then so does all of that.