Characters
Bottom line is we're around each other an' this thing, it grabs hold of us again at the wrong place, at the wrong time, and we're dead.
— Ennis · Brokeback Mountain

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker warns that when the two of them are together, the feeling between them takes hold again, and if that happens in the wrong place at the wrong time, it could be fatal. The tone is grim and fearful, treating attachment as a real danger.
Context reviewed