Potty training

So we started the process of potty training. My daughter is doing great with peeing on the toilet. Then after a few weeks I decided to try her on outings…..😳 . She refuses the public washrooms she is terrified of them… the hand dryers the noise. We have the small toilet seat at home that she climbs up on so it isn’t the toilet itself it is the public restrooms. I have no idea even how to approach this. I tried to desensitize her by going myself but she is still terrified. She held her pee at the zoo for 6 hours….. 😳. Poor thing