Ein|sturzen - to Collapse

I have been first-aid trained on three separate occasions, and in each case after less than a week, I’ve felt entirely unqualified and shamefully inadequate should an emergency occur. At the time it seems so easy and all makes perfect sense, but as the memory fades, so the paranoia builds. It’s the same with any training course. Around six months ago I was trained to use a Genie cherry picker to basically reach high stuff. Our instructor was intent on filling our heads with his numbingly irrelevant stories of ladders and steps. He also spent several minutes stroking a ladder, acknowledging its brand and informing us repeatedly how it was ‘a fairly substantial piece of kit’, how it was ‘the European gold standard of ladders’ and, well, I’m losing consciousness just thinking about it. However, despite the appalling dullness of the whole occasion, I felt reasonably learned, and quite confident about operating safely at height. Now, six months down the line, I’m convinced either I’ll die, or I’ll kill someone else, or both when I miss a blindingly obvious safety precaution and topple into crumpled bone-heap. I feel the same way about applying first aid. Do you give a diabetic a teaspoon of sugar if they‘re on the verge of collapse? Or was that something you definitely don’t do? Anaphylaxis? Can you administer adrenaline without their consent? Or could you get sued? So many things I could probably find out with a quick Google search, but I’ll probably just bury my head in the sand and hope I never have to do anything.