Responses
I’m thinking it’s the doctor. Reporting his daily activities as input to track if daily routine has any impact to his road of recovery with the support of latest ‘medicine’. Seems sus. Since Baek Cheolmin also mentioned th effect of H-100 drug is better with certain ‘medicine’. Truth might be, Jaeyoung is the chosen rat lab for their drug research.

Can someone explain the last panel to me? I think the phone belongs to Jaeyoung and he seems to be reporting his daily movements to someone. Maybe he forgot to text his daily routine for the day because the person he's sending the updates to, messages a '?' which implies the receiver is waiting for the text of the day.
What I don't get is what could be the meaning of this, if someone can dumb it down for me please?