Hi.
Both switch connections are internal nodes of the circuit, so adding extra circuitry there is likely to just make the circuit not work. If you want extra behavior around the switch turning on and off, we recommend adding that to the powered side of the switch (e.g. add a circuit that does your beep thing when power gets applied). Triggering something when the switch turns off is a bit more tricky, but you can see suggestions for how to do that in this forum thread.
-Claire