It's just left. (bus) - When will it be here again?

[Topstudent]

I'm trying to write something: Mark and Derek came up to the bus stop. Mark looked at the bus schedule, then his phone...

Mark: It's just left.
Derek: When will it be here again?
Mark: In half an hour.

Note: It's one bus that drives the same route over and over all day.
Question: Could you please tell me what you would find natural in each of the two bold-faced dialog sentences?

 

[emsr2d2]

I'm trying to write something. Mark and Derek come up to the bus stop. Mark looks at the bus schedule, then at his phone...

Mark: It's just left.
Derek: When will it be here again?
Mark: In half an hour.

Note: It's one bus that drives the same route over and over all day.
Question: Could you please tell me what you would find natural in each of the two bold-faced dialog sentences?

Derek would say "When's the next one?"
Mark would probably say "We just missed it" but yours isn't wrong.

 

[Topstudent]

Derek would say "When's the next one?"

Also, if it's the same bus?

 

[emsr2d2]

Also, if it's the same bus?

Do you mean "Would you say the same thing if it's the same bus?"? If so, yes. It doesn't matter if it's the same physical vehicle or a different one. What you're really asking is "When's the next bus service due to arrive at this stop?"