A more appropriate response which is unfortunately not trained as often as it should be in our modern, automation-dependent world would be the old "click-click, click-click". Those of us from before the MPL / G1000 generation learned to fly on aircraft with no "bugs" on the airspeed indicators; most of us learned to fly an ILS raw-data with a pair of crosshairs or maybe an HSI in more recent times. When flight directors, FMAs, speed and heading bugs etc go kittywompus on us we should still be able to "step down" the automation and handfly comfortably on basics. A missed approach is another safe option. It seems like these skills are discouraged in most SOPs and training departments these days, and that is a disservice to pilots who could benefit from maintaining those skills, such as this situation.
Have the chart in front of you. If you lose your G/S or ALT SEL on your FMA, turn it all off and fly the airplane like it was a very fast Seminole. This is how it should be trained and skill should be mandated. We have to log autolands to maintain currency in my company; why not mandate log at least one raw-data fully hand-flown approach (in VMC even!) every 90 days? Probably get laughed out of the building to bring that one up to a training department anywhere in the world these days, which is sad. If that were trained to proficiency, instinct, and recency to the extent autoflight is, these kind of incidents would decrease.
Never going to happen. Oh well, starting to show my age, I guess!
