At the beginning Norm tells Sam it's his 15th wedding Anniversary. Two episodes earlier Gus the previous bar owner stated he sold the bar to Sam 17 years prior, and he also stated Norm and Vera when first married spent a lot of time in the bar. That would have made their Anniversary way more than 15 years.
The door to Rebecca's apartment didn't close by itself; it was obviously pushed by a crewman standing behind it.
When Sam beats on the wall to alert Frederick Crane, it's the outside wall, not the interior wall with Frederick's bedroom on the other side.
It has been stated in multiple previous episodes that Norm has a key to the bar. Sam could have borrowed this key rather than run all over town.