At the end, the computer code-breaker cracks the code for the safe room as 17052014 and the safe room door opens. At the start of episode 4 Georgina has the code written on her arm as 15072014 and she uses this to open the room. All future references to the code are 15072014, the date of her wedding.
The passcode for Constantine's saferoom was shown as 17052014 on Robert's laptop. However, when it had been written on Georgina's arm it was 15072014. The 15072014 passcode is then successfully used for numerous entries to the saferoom.