@Nago Pits of lava aren't that common near your average medieval countryside even if the main character had magic foresight powers. And I doubt the average villager will hold a letter for a month before sending it to the order because a random stranger told him to, even assuming he can somehow wander around town without supervision. Additionally, it's unlikely his cover would have lasted a month since he already slipped up multiple times during his awakened state. Lastly, I doubt the order is giving through sound seeing as some of the lesser undead don't even have eardrums. As such, it may be possible that the master can just magically transmit the order for him to return assuming he tries to run away (and it'll also 100% blow his cover).
Anyways, what he did was fairly logically assuming that BS powers like having 120 lives isn't a common ability. That said, it probably wouldn't have been better to wait until he saw how the necromancer dealt with danger before he acted but with the order coming, he didn't have the time.