Sometimes a dealer will suddenly insist on changing the venue of a deal, leaving a u.c. without any backup in the area.
The targets were handcuffed and separated; the u.c. was also handcuffed to preserve his cover.
Spending time around C.I.s makes it easier for a u.c. to pick up the slang of meth and its users.
A dealer might offer a u.c. a hit of meth to seal the exchange.