It was an anxious twenty minutes for all of them. At last they heard the deep metallic clang of the heavy steel door being struck. Together they turned the locking wheel, and then heaved the door enough ajar for him to enter. He stumbled in and removed his cloth mask, which was dark grey from the ash. It was everywhere; in his hair, all over his clothes, and evidently in his lungs. Immediately, he began coughing violently. He gestured for water. He spat his first mouthful straight out onto the floor, where it sat in a deep grey pool. He drank again, and this time he let himself swallow: he let the water cool his burning throat. All of them looked at him expectantly.
Jonah took the radio out of his pocket and placed it down on the table by his side. It was hissing static.
“Nothing. I’m sorry.”
Wearily they turned and headed back into the heart of the shelter.
This isn't a hook, it's a first page. You've got four sentences starting with "he" in one paragraph which is a reliable indicator for the presence of clunk.
You've narrated events to the exclusion of description or reaction. In other words you could be writing for the Police Blotter Quarterly and be ok.
There are a variety of examples of hooks that work and good form even for books I didn't much like listed before. Study them. Emulate them.