Calm protects skills panic would temporarily lock away.

Under real panic, capable people forget things they know perfectly well. The knowledge has not gone anywhere, it has simply become temporarily unreachable, which is why practised professionals train specifically to stay calm rather than only to be skilled. Composure is the key to the room where your abilities are kept.

If you have surprised yourself by fumbling something you know well, the problem was probably access rather than knowledge. Practise the skill under mild stress so that the retrieval works when your system is up. The skill alone is not enough.