Learn Hardcore Russian: Мы идём по коридору к лифту. - We are walking along the corridor to the elevator.

идти/идём = to go on foot, to walk (that’s the case here).
ехать/едем = to go by vehicle (car, bus, train, elevator, etc.). If you were moving by some transport, you’d say Мы едем.

What’s the difference between идём and ходим?

Both are “to go (on foot)” but:

идти/идём = one-time, unidirectional movement right now or on one route.
ходить/ходим = habitual or multi-directional movement (back and forth, from time to time). Compare:
Сейчас мы идём по коридору к лифту. We are walking there now.
Мы часто ходим по коридору к лифту. We often walk to the elevator.

Does Russian have a separate present continuous like “we are walking”?

No. The simple present of an imperfective verb covers both simple and continuous meanings. Мы идём can mean “we are going (now).”

Why is it по коридору and not по коридоре?

Because по in the sense “along/through/over” takes the dative case. Коридор in the dative singular is коридору (masculine noun ending in a consonant gets -у/-ю). По коридору = along the corridor.
Note: Static location uses в коридоре (prepositional). Motion into uses в коридор (accusative).

I thought dative often ends in -е. Why коридору with -у?

It depends on gender/declension:

Masculine/neuter nouns ending in a consonant: dative singular = -у/-ю (e.g., город → к городу, коридор → по коридору).
Feminine -а/-я nouns: dative singular = -е (e.g., дорога → по дороге, станция → к станции).

Why is it к лифту? What does к mean here?

К means “to/toward” and takes the dative case. К лифту = toward the elevator (approaching it). It focuses on direction, not necessarily entering it.

How is к лифту different from в лифт or до лифта?

к лифту (dative): toward the elevator (direction/approach).
в лифт (accusative): into the elevator (you cross the threshold).
до лифта (genitive): as far as the elevator (up to that point, implying reaching it).

Could I say ко лифту instead of к лифту?

No. The variant ко is only used before certain words for euphony (e.g., ко мне, ко всем, ко входу). With лифту you use к: к лифту.

What are the main case forms of лифт I need here?

Singular highlights:

Nominative: лифт (the elevator)
Genitive: лифта (of the elevator)
Dative: лифту (to/toward the elevator)
Accusative: лифт (into the elevator → в лифт)
Prepositional: о лифте (about/in the elevator)
Instrumental: лифтом (with/by means of the elevator)

Is the word order fixed? Could I say Мы идём к лифту по коридору?

Word order is flexible. Мы идём по коридору к лифту presents the path first, then the destination (very natural). Мы идём к лифту по коридору is also correct but puts a bit more emphasis on the destination first.

Can I drop the pronoun Мы?

You can, but be careful. Идём по коридору к лифту can be heard as a suggestion/command “Let’s go along the corridor to the elevator.” Keeping Мы makes it clearly a statement about what you’re doing.

How do I pronounce идём, and why is ё important?

Идём is stressed on -дём and pronounced like ee-DYOM. The letter ё is always pronounced “yo” and is always stressed. In print, ё is often written as е (идем), but you still pronounce it “идём.”

What if I want the perfective/aspect nuance like “Let’s start going” or the past?

Use the perfective пойти/пойти family:

Future/intention: Мы пойдём к лифту. We’ll go / Let’s go to the elevator.
Suggestion: Пойдём к лифту! Let’s go to the elevator!
Past (set off): Мы пошли по коридору к лифту. We set off along the corridor to the elevator.

Are there alternatives to по for “along” here?

Вдоль коридора (genitive): along the length of the corridor; emphasizes the line/edge.
Через коридор (accusative): across the corridor (from one side to the other), a different geometry from “along.” In your sentence, по коридору is the natural choice for moving within/along the corridor.

How would I say “by elevator” (using the elevator as transport)?

Use на + instrumental for means of transport:

Мы едем на лифте. We’re going by elevator. For going up/down specifically: подниматься/спускаться на лифте.

What happens in the plural with по?

With plurals, по still takes the dative plural:

по коридорам = along the corridors (not по коридорах). Similarly: по улицам, по музеям.

Which question words do these parts answer?

Идём answers “what are we doing?” (action).
По коридору answers “где?/по чему?” in the sense of route (“along where?”).
К лифту answers “куда?” (“toward where?”). This pairing of route (по + dative) and destination (к + dative) is very typical.