Okay, I've listened to that line a few dozen times and while I can see how you might think it's Sigourney Weaver, my first thought is that voice sounds like Sean Young. Which makes sense both practically and within the film (of course Tyrell would use Rachael's voice as his home personal assistant).What am I referring to exactly? The female (presumably computer) voice on Tyrell's intercom. Just one line of dialogue; "Blue entry. A Mr. J.F. Sebastian. 16417."
Can someone else listen to this and tell me I'm mishearing things because I swear that sounds like Sigourney Weaver getting an uncredited cameo. Which would make it her first time as a computer voice, but certainly not the last!