He can talk out loud to the implants voice, and hes the only one who can hear it.
In the film, written and directed bySawco-creator Leigh Whannell, the Tom Hardy-throw in is Logan Marshall-Green.
In theupcoming movieVenom, which shares an almost identical plot, the Tom Hardy-pop in is Tom Hardy.

Credit: Ben King/BH TILT
Thats not to say a movie is necessarily bad for treading on well-worn territory, butUpgradedoes little else.
Does it matter that Grey doesnt think to report this incredibly relevant information to the police?
Of course it doesnt.
(Perhaps it was force of habit on Whannells part after working on so manySawmovies.)
This is not played for laughs.