Very simple.
If you can't take the stairs safely, take the lift. If you can take the stairs but need to keep still, stay right. If you are want to get to your destination quicker, take the left.
It's the same for cars and we have the same functionality.
Stop making a situation complex, if everyone abided by the rules above, we'd be fine but it's the people who switch sides, that's the issue.
People get into car accidents, same as on lifts. Stay in your lane!