Suppose the ice on a server is arranged, outermost to innermost: Sensei, Wall of Static, Cell Portal, all rezzed.
If the runner does not break the subroutine on Sensei, breaks the subroutines on Wall of Static, is returned to the outermost ice by Cell Portal, and does not break the subroutine on Sensei the second time they encounter it, how many subroutines does Wall of Static have the second time they encounter it?
Three: the native subroutine, plus one from each encounter with Sensei?
Or four: the native subroutine, plus one gained during their first encounter with Wall of Static, plus two more gained during their second encounter with Wall of Static? Thanks for the question. The answer is three: one + one for each time Sensei has been encountered.
I checked some previous ruling and wanted to follow up on this. Sensei's original subroutine is still active, and so the Wall of Static would actually have four subroutines instead of three. Sorry for the confusion.
Suppose the runner encounters Sensei and does not break the subroutine, and then encounters Ice Wall, which has been chosen as the target of Femme Fatale. Does it cost 1 credit to bypass Ice Wall with Femme Fatale (because these are simultaneous conditional abilities, and the runner may trigger Femme Fatale before Ice Wall gains a subroutine), or 2 credits (because 'for the remainder of this run, each piece of ice encountered except Sensei gains "End the run" after all its other subroutines' is a constant ability)?
If the previous answer is 2 credits, then suppose instead the runner encounters Sensei and does not break the subroutine, and then encounters Komainu. Does the end-the-run subroutine come first, because it is already present, as the first subroutine, when Komainu gains its net damage subroutines, or last, because Sensei says the end-the-run is after all other subroutines? Or something else entirely? The Sensei is creating a constant ability that gives each piece of ice an additional subroutine. So when you initially encounter the Ice Wall, it costs 2 credits to use Femme Fatale in order to bypass it. With the Komainu, the subroutine will be by itself, unless the Runner has cards in hand. If the Runner has cards in hand, then the subroutine drops to the last position as soon as the Komainu gains its subroutines.