Ethics question

Anyways I got a good ethics question for you
[10:35:20 PM] Himiko Werckmeister: lets suppose you at a random university campus
[10:35:34 PM] Himiko Werckmeister: the whole building is nearly pitchblack
[10:35:58 PM] Himiko Werckmeister: you know a dangerous serial killer is on the loose in the building...
[10:36:21 PM] Himiko Werckmeister: and you have a knife out to protect urself just incase that guy comes to jump on you
[10:36:42 PM] Himiko Werckmeister: With this in mind you walk cautiously in the halls
[10:36:56 PM] Himiko Werckmeister: watching for this serial killer as you you
[10:37:06 PM] Himiko Werckmeister: *walk on
[10:37:37 PM] Himiko Werckmeister: Around 40 meters in, you see a girl infront of you
[10:38:02 PM] Himiko Werckmeister: and to your horror the serial killer is walking towards her
[10:38:16 PM] Himiko Werckmeister: brandishing a machete
[10:38:58 PM] Himiko Werckmeister: you decide to stab her [keeping in mind vital organs] to protect her from potentially being killed by the serial killer
[10:39:42 PM] Himiko Werckmeister: a few days later you walk by the hospital wing passing by her hospital room
[10:40:43 PM] Himiko Werckmeister: the girl catches a glance of you
[10:40:49 PM] Himiko Werckmeister: and wants to know u better
[10:41:04 PM] Himiko Werckmeister: would you approach her or not?