
Originally Posted by
Apostate
This is complete speculation on my part, but first of all it may be easier to see while crawling through those vents if you have large, sparkly animal eyes. Secondly, and this is less likely I think, the LS's have somehow been modified to 'see' Adam.
For example, after the PC gains Electrobolt, the LS observes that she can see "light coming from his belly." This may be what happens whenever anyone becomes a user, or it may just be an Electrobolt side effect. On the other hand the Sister doesn't seem to be too surprised by it, and I kind of got the idea she'd seen it before. So, let's say there are corpses littering Rapture, and all of them have a limited amount of genetic material. If two LS's happen by the same body on different occasions, the later girl will end up empty handed, having wasted her time. So perhaps the change to the eyes allows them to differentiate between bodies that have been scavenged and those that haven't?