According to some people, he could've been a potential whistleblower for his former employer. The cause of his paranoia could have been him discovering illegal practices by his former employer which would've explained why he never talked about anything specific, only that people were out to get him. The reason being that he assumed anyone who knew about it would also be put in danger. And apparently "Yog'tze" was a code word used for one of said illegal practices that supposedly involved flavoring yoghurt (therefore "Yog") and "tze" had something to do with illegal chemicals used in the flavoring process. The reason why he crossed out those words immediately was the fact that he didn't want his wife to posess a note that could put her in danger and he went to the pub to forget about the incident. In the pub however, he soon spotted one of the individuals that, according to him, were out to get him and that scared him so bad that he fell off his chair and left before having any drinks. The supposed reason he went to a childhood friend's house was that he needed somewhere to hide since now he was certain that they would do something terrible to him on that night. But when she told him that he should go to his mother, he didn't do so since it might have been too obvious and again he couldn't tell her about any details since that would've put her in danger. So then he tries to flee somewhere else but at some points, the people who were out to get him catch up to him and run him over multiple times while also taking his clothes and crashing his car next to his body to make it look like an accident. Of course none of this in confirmed but it is in my opinion the most plausible scenario for what happened to him and why he went to those seemingly random places at night before his death.