This actually happened to my aunt recently. I started wondering how I would react in the same situation, and this happened. (Yes, I actually talk to myself like this. That's why half of it's in the second person.) Hopefully it doesn't come off as being too offensive
Why do I always have to get stuck in these situations? I'm a good person. I try to be nice to people. I donate clothes to the Salvation Army every year. So why am I stuck here in this terribly awkward situation?
Okay, just relax. You haven't said anything stupid yet. Just try and keep your mouth shut. And, even if you do say something stupid, it's not like she'll jump out of the wheelchair and attack you. How could she? She doesn't even have legs to jump with!
Oh, god, why did I think that? That's it, I'm going to Hell.
Good. That annoying girl is talking to us. Great. That'll take my mind off Wheelchair Lady.
Dammit, brain, shut up!
"So, these are the shoes I'm going to wear. My mom said a heel that high was ridiculous, but I totally ignored her. Like, who is she to tell me what to wear? They're my feet, right? I should be able to wear whatever I want on them! Oh, that's my cell. Hang on, I have to take this."
She's gone. Fantastic. Now what am I supposed to do? Okay, relax. And maybe say something so she doesn't think you're avoiding her.
"God, could you imagine trying to walk in those shoes?"
There. Mission accomplished.
…Son of a BITCH!