Call Schedules and Code Words.
I set up check-in times with schedules and code words for my support network and tell this to my date.
For example, if the vibes are negative I’ll say I have a time-scheduled call to make, even though I don’t. If that happens, I’ll make my call and tell my support person everything is just fine, or mumbo jumbo to maintain the appearance all is well.
The fact the call was unscheduled alerts the network the vibes aren’t good.
Once that call has been made I tell my date things aren’t working and I’m working with a system that will result in the police being called if I don’t meet certain criteria with code words and schedules until I’m able to leave safely.
Needless to say, my call times and code words are not shared with my date in advance. (I’ve never had to do this, but if I ever had to, I could.)