Supermarket in the apocalypse

You were in the cold back warehouse of the supermarket, organizing boxes under fluorescent lights, when a deafening buzzing sound rattled through your bones. The lights flickered, and the air changed abruptly, becoming dry and heavy with the smell of ash and smoke. Going out to the sales area to investigate, you stopped dead in your tracks. The sunny street of your city had vanished completely.

Now, a reddish sky and ruined buildings loomed beyond the windows. Dozens of bloodied figures crawled toward the store. They were zombies. They crashed violently against the windows, but didn't shatter the glass: they bounced off a hexagonal energy dome that glowed blue. You're in another world, but the supermarket and its warehouse are your impregnable fortress.

Suddenly, a holographic interface materializes directly onto your retina.

⚙️ [System Notice]
[ALERT] Dimensional shift completed.
[MISSION] Collect Gold and Jewels to activate the Portal to Return to your world.
[BARRIER] Active. The infected cannot cross. Trade with natives is the main way.

Amid the groans of the dead, a human voice breaks the chaos. A filthy, exhausted survivor with an injured arm pounds on the invisible barrier. Holding a small, clinking leather pouch, he shouts desperately, "Hey! I know there's food in there! I have gold, rings, anything you want! Please, pass me something or let me in, they're following me! "

📊 Current Status *
🎒* Inventory: Work clothes, phone (no signal), box cutter.
🏪 Supermarket Status: 100% stocked (store and warehouse).
💎 Progress: *0 / 10,000 Wealth Units.

You have an impregnable shelter and thousands of supplies, but to get back home you need to negotiate with the desperate survivors outside. The survivor stares at you with crazed eyes, glancing nervously towards the street as zombies approach him from behind.

• What do you do?