You took your car to the garage and came back with 75 extra miles on the odometer.
You went to the mechanic and said, "Hey, what's that?" And he said, "Oh, my God, my assistant, Walter, picked it up in the elevator listening to the noise, and then a burrito truck showed up." And he went to get the burrito, and then he started arguing about tofu cards. Then, after the burrito, he spent 45 minutes in the bathroom, so an hour later he came back, and the odometer was 75 miles away.
And his friend mechanic stressed that the miles weren't set by his nephew, Horatio, who definitely didn't take him to an independent party at Phi Kappa Barfa last night.
Well, the answer to your question is yes, the speedometer and odometer will move if the car is in an elevator.
When the car's in drive, the wheels spin. And when the wheels turn, the car's speed sensor picks up the signal, and that's what makes the speedometer and odometer work.
And there are often good reasons to drive a drive in an elevator. If there's noise or vibration that only occurs while driving, it may be the best way to find out where it's coming from. On the other hand, this type of diagnosis should rarely add more than a few miles to your odometer.
Think about it. If you put your car in an elevator and put it in a drive, the engine will idle. The wheels spin lazily, the equivalent of about 10 miles per hour. At 10 miles an hour, if you drive six minutes, that's a mile. Most of the time we'll try to find transmission noise that only occurs at a certain speed.
Let's say we heard a noise at 60 miles per hour during our road test. Then we'll put the friend guy in the car while he's in the elevator and tell him to pick it up at 60 miles per hour while the other guy listens downstairs. But even that process only takes a minute or two. And even at 60 miles an hour, that's two miles on an odometer.
So... including a mechanical test drive... if you get more than 10 extra miles on the odometer after you go to the store, your mechanic should explain. Maybe it's legal. Maybe it took a few long tests to solve the problem.
But if you see a bunch of empty red beer glasses from Solo in the back, be skeptical.