How does the abyssal rune help me find the exit?

[kuniqs]

There's a message that the rune guides me to the exit or something. What happens exactly? Does the chance of a random tile being the exit rises or something?

[ZipZipskins]

yes, by a dramatic amount.

[le_nerd]

To showcase the dramaticity of the increase, on certain (stealthy) characters I will just go down and snatch abyssal rune because its the fastest way to exit abyss.