Reading an event log file

Hello everybody, I will start telling that I'm sotty for my english (I'm italian) and I don't have in depth informatic knowledge (sorry again). Due to a project for my thesis, I need to read the log of the events that happen in Unity based game. The problem is that, opening the file of the game session I can't locate the time column. The only value that keeps increasing through the session is written in the form xxx.xxx.xxx To understand the time unit, I made a video of the game session registering the time (on screen during the game) of every single event. The game lasted 32.7 seconds, while the maximum vaue of the column was 4.217.185. What is strange is that if I subtract two values of the same series (e.g. 2.290.198 - 2.030.357) I obtain the correct delta time (259.841 = 2,6 sec) but of course it doesn't work through different series. Not being a programmer (I'm studying psychology), I don't know how the game saves the time of the events. Any guess?

A link to the csv event file https://www.dropbox.com/s/oq6c8f32l7g5kvl/Book1.xlsx?dl=0

Thanks!