The isekai script seems to be a modified runic alphabet transcription of english. (Some characters have been switched for some reason and others are upside down, but a lot of it is still correct)
* Actually, after rereading it and looking at a few more of the alphabet sets, it is fully correct except for the first "ur" and the first "cen" being flipped (vertically and horizontally respectively) but then correct for future instances (no clue why).
I love the sfx for this! But I got to say that sounds like an absolutely horrible way to go, being suffocated by rats forcing themselves down your throat and up your nose.