It let the WAU monitor their conditions — you know, recording their vitals and brainwave activity and stuff. Part of its “keep humans alive” thing, back when it still did what it was supposed to. The company that made the WAU and the blackboxes was really pushing for them to use all this stuff, so they were company policy.

[ He’s not gonna think about how he has one of their blackboxes, or at least enough of it that the Compound Examiner could read its data and identify Imogen. That just.... yeah. ]

Didn’t end well once the WAU started malfunctioning.