Need the combination

👍

I'm imagining the joke being ironical, with the cuts being on their fingers.

Medical supplies are valuable and junkies exist, so people need to lock medical supplies to keep them from being stolen. In the event of an emergency, anyone who would actually need to access the medical supplies within either knows the combination and is able to open it quickly, or has the sheer strength to brute force that lock right off the latch. It's the same deal with fire extinguishers, which also have reinforced glass because the contents of the can are under pressure and idiots be idiots.

Postscript: It says "emergency medical supplies." No one's accessing this thing for a minor scrape. This is being accessed when someone's bleeding out or otherwise needs sudden medical attention. And people who know how to open this will know its contents, meaning that this will only have to be opened when the supplies within are needed, not because someone randomly fell and nobody knows what's inside. Instead of leaving it unlocked and risking the stuff being taken and misused, you would *want* to keep it locked so they can't be taken, but also easily accessible when it's actually needed (because simple padlocks like this are easy to unlock).