Is this unsafe?

About two months ago we noticed our house was not heating up properly. We’d set the thermostat to 70 and it would read at 50. After confirming with our own thermometer, the house really was that cold. Eventually, an hvac technician who’s worked on the house before came out and noticed there is no intake vent for the system, only output vents. His temporary solution was to open this panel on the furnace as to allow the system to get more air.

For context: our heat is gas powered. we started renting this house in the fall when temps were higher and only noticed when we switched to heat and the temps fell. Our landlord has extremely poor communication, hence how long it’s taken to fix this issue. Are we valid in thinking this is a fire hazard/isn’t safe?

We live in DC if that matters.