doc: script actions *must terminate* or they will be killed
@@ -484,8 +484,9 @@ with an additional set of environment variables:
the program, if it exited normally, or the signal name (`HUP`,
`TERM`, etc.) if it exited due to signal
-The scripts have a default execution time of 3 seconds before they are
-SIGKILLed, this can be adjusted using the above `kill:SEC` syntax.
+These script actions *must terminate*, so they have a default execution
+time of 3 seconds before they are SIGKILLed, this can be adjusted using
+the above `kill:SEC` syntax.
> **Note:** the `pre:script` _must_ be idempotent, because a service
> can transition between READY and HALTED states any number
