diff --git a/test/watchdog.ml b/test/watchdog.ml
index 99c9040..dbc10b8 100644
--- a/test/watchdog.ml
+++ b/test/watchdog.ml
@@ -39,6 +39,8 @@ let dying _ =
     \      turned into a failing run.\n"
     !label !budget;
   flush stderr;
+  (* [exit] rather than [_exit]: the rows that did pass are in stdout's buffer
+     and a watchdog that threw them away would be worse than the hang. *)
   exit 2
 
 (* Re-arm the backstop for whatever is left of its budget. One second is the