Things are usually easier in confined water. This is why they do them in confined water. However, once you get out into open water, if you have not resolved everything you can in confined, things go poorly.
Start asking "why". Find out why your instructor thinks you panicked. See if there is something to it. Or see what assumption the instructor us making. Keep an open mind and just try to understand WHY the instructor thinks you panicked.
Uhm, my instructor slaps my hand when I put it on the inflater control. You want to be weighted so that you have a minimal amount of air in the BCD. The air in your lungs is used to control you going up and down. Breath normal and stay at the current depth. Deep breath and you should rise a little. Breath in a little slower and you should start sinking.
As you go deeper, because air compresses, you will need to add a little air to the BCD. As you surface the air in the BCD will expand so you will need to remove a little air.
If you are wearing too much weight, you will have to add an remove a LOT of air to the BCD. This makes things harder. Search this board for tips on improving your buoyancy and how to make sure you are properly weighted.
WHEN you need to add or remove air from your BCD, you use short bursts or short dumps. I'll do this maybe 4 or 5 times during the course of a 50 minute dive. Probably once or twice if I was keeping above 10m.
Did you mention to the instructor that you occasionally found your regulator full of water? Did this happen when you were in the confined water? Are you using the same regulator in the open water that you used in the confined water?
Two thoughts pop to mind, you are not holding the regulator in your mouth and water is leaking in or there is something wrong with the regulator. If you had the problem in the confined and open water it doesn't tell us which is your problem. If it was fine in the confined water but not the open water then I'd suspect you are busy concentrating on other things and you let water leak in. Don't bite down hard. That does not help. Keeping water out of your regulator is like using a straw to drink. If I don't keep my lips pursed around the straw, air gets in and I have a hard time drinking. So, use your lips to keep the water out, if that is the problem.
If you have water in your mouth do the following. Spit/cough out into the regulator. Stick your tongue into the opening for the regulator (use your lips and teeth to keep holding the regulator in your mouth). Push the purge value button. Take your tongue out the regulator. Breath in. This method works even if you don't have any air in your lungs/mouth. Practise this even when you don't have any water in your mouth. Practise this above water.
Practise is the key. If you don't feel safe then don't do it. If your instructor is going to rush you, get a new instructor. People DIE doing this wrong. By rushing you, your instructor is risking your health and possibly your life.
All my instructors (I've had four; DSD, OW, refresher, AOW) have told me, "this is not a race. take your time."
If you are paying for this, ask for your money back. Complain to the management. If this is included with the vacation, complain to the management. Tell them you are currently discussing this incident on a scuba board with over 100,000 scuba divers but that you haven't mentioned the the resort name... yet. In other words, if they got their money and there are no consequences for them, they will continue to treat you badly. If they realize this one incident could taint them for 100,000+ potential customers they might be a little more helpful.
