Yes, usually it happens at the same time, although I have seen patients who have had weak pulses but not breathing (usually following an overdose of an opiate drug such as heroin)
Stop by, becasue you want them to come by and say hi or something but when you say "bye" it's as if they are leaving so you are saying good bye to them
I would say a stop line because if theres a stop sign most likely there is a stop line.... and in some places like my nabior hood people steal stop signs so watch for the line....