if (pattern ...) is not a rule unto itself and so it does not do rejoinders. You can always flip back and forth, like this
if (pattern love) {^reuse(~mytopic.rule5)}
topic: ~mytopic ()
s: RULE5 (?) I love speed too.
Or even directly call the topic instead of using if….
^respond(~mytopicx)
topic: ~mytopicx()
u: (love) I love speed too