Don is heating up some milk on the stove and it boils over during his flashback. Moments later, we see the inside of the pot and its perfectly clean.
Don and Sal visit the London Fog company and talk about how long London Fog has been a client of Sterling Cooper. Then moments later Joan reads a list of companies that Sterling Cooper has as clients which Pete and Ken will manage, and she does not mention London Fog at all.
Harry says there is no reason making more than $40k a year because the taxes would be 69%. But he is mistaken, US tax brackets are progressive. You are only charged the higher tax rate on the difference from the last lower bracket on more income. At $44k a year he would be in the 72% tax bracket but only be paying 54% before deductions.
Don has just got down the fire escape and a fire truck is sitting there already.