description - How to avoid pages of dialogue?

I'm starting my story with my protagonist found (by the police), bleeding at a crime scene. When he wakes up, he has no recollection i.e. he's lost his memory. He's interrogated by two Inspectors, but as he doesn't remember anything, it's mostly a one-sided conversation with the Inspectors essentially describing the crime scene.

My Question: How can I avoid such long 'walls' of one-sided dialogue and make the description more interesting for the reader?

Answer

To me (and IMO) a wall of dialogue is typically an under-imagined scene, and it needs to be longer.

What is your character seeing of the setting?
What about in the detectives?

What does he disagree with?
Why is he so passively listening to this stuff, why isn't he interrupting and interrogating his interrogators?
Why aren't they getting frustrated and angry with him, and telling him to quit asking questions?
Why doesn't he have any difficulty imagining what they claim?
Why doesn't he fear being a suspect in some heinous crime?
Why does he trust these detectives?
Do they ever gesture? Get up? Sit down? Shift? Or are they all just disembodied talking heads?
What does their body language tell the MC?

Walls of dialogue, like every other scene in your book, need a healthy dose of conflict to remain interesting. In conversation, conflict is generally verbal and emotionally expressive, to convey disagreement, grief, confusion, withdrawal, hurt, anger, humor, sarcasm.

Even in this, you want to Show, not Tell. Telling is reciting facts, Showing is describing a character's reaction to facts, the consequence of learning this new information, how it affects them.

Remember your job, as an author, is to assist the imagination of the reader and keep it as close to what you imagine as you reasonably can. You can't assist them if you have not fully imagined this scene yourself! Your job is not to just convey "information" about the setting, you must give the reader the experience of waking up disoriented in a hospital room not knowing WTF happened, and then being interrogated by police officers that are guarded and may think you are a criminal or killer, so whether they are hostile or not they feel hostile to you.

Imagine your scene and your characters better. This will break up the dialogue, it may even triple the length of the scene, but readers don't care about that! As long as you keep feeding them morsels of conflict and feelings, of thrust and parry in this conversation, they will keep reading.