I'll do it inside my car. I know it will be less comfortable than a hotel bed, but my family is already suspicious and watching me all the time I'm in home, so I can't just leave home and spend a night in a hotel. There are high chances to get interrupted by some member of my family looking for me.
So, I'll have to do it inside my car, during the lunch time, in the parking place of my work.
I'll drink SN at 1PM, usually I come home at 6PM, so, my family will notice something's wrong only 5 hours after drinking the SN.
I hope everything goes as planned.