You can check out at any time, but you can never leave. What does that mean?

This should be understood in combination with the previous lyrics:

You can check out at any time, but you can never leave.

You can check out at any time, but you can never leave.

But judging from the meaning of the whole song, it can be summarized as the implied meaning: "Even if you leave here, your heart will stay here forever."

Composite indefinite pronouns

Compound indefinite pronouns is a indefinite pronouns composed of some-, any-, no-, every- plus -one, -body, -thing, -where and -time. Compound indefinite pronouns includes: someone, someone, something, somewhere, anyone, anyone, anything, anywhere.

Nobody (nobody) has nothing (nothing), no place (no place), everyone (everyone), everything (everything) is everywhere and so on. These compound pronouns have the nature of nouns and can be used as subject, object or predicative in sentences.

Reference object

1, compound pronouns with-body and -one are only used to refer to people. The compound indefinite pronouns with-body and the compound indefinite pronouns with -one are exactly the same in function and meaning and can be interchanged. Only when -body is used, it is more popular, mostly used in spoken language, and when -one is used, it is more elegant, which is more common in formal occasions and written language. For example:

Someone is crying in the next room. Someone is crying in the next room.

No one is stupid. Nobody is stupid.

2. The compound indefinite pronouns with -thing is only used to refer to things. For example:

Are you going to buy anything? Will you go shopping?

I can't hear anything except your voice I only heard your voice.