I really can't get my head round this rider swap thing, and this whole situation is massively triggering my anxiety

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So there's me and my partner, I can't wait in a long line because I need regular bathroom breaks, and I can't join and rejoin the line multiple times in my scooter. So I have to wait outside the line on my own (which I can't really do in case I need help from my partner), my partner is in the line on her own, and what? Texts me when she's at the front at which point I go via the LL and join her?
Maybe I'm being stupid, but I don't understand it, and that solution sounds so miserable. Just our trip would involve loads of time by ourselves every day. I get that there has to be a solution and I wish I could be in a line for 30 minutes plus, but I can't. Frustratingly, I just don't now what the solution is, I can't think of anything other than requiring medical evidence, which is fairly common practice here in Europe, but sounds like it isn't in the US.