I’m struggling to understand the scenario you’re describing. So the alarm goes off because an apartment is on fire. In response to this, everyone else waits until the fire brigade shows up to attempt to exit? I’m pretty sure if people are going to evacuate, they’ll do this in response to the alarm, and not wait and block the stairs. Also I’m pretty sure the fire brigade can tell them to get the out of the way to get up the stairs if necessary. How narrow are these stairs anyway? And why did everyone not evacuate before the fire brigade showed up?

I just find the “apartment on fire, but everyone is blocking the stairs so the fire brigade can’t get to the burning apartment” scenario to be far fetched. Are there documented cases of this? Because there is at least one documented case of people sheltering in place and the building burning around them.