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In Maryland justification for constructive eviction exists when the landlord is renting the property illegally. Call the fire department for an inspection and see if they condemn the property. That will certainly allow you to leave.
Now constructive eviction is a defense, not an offensive move. What this means is that should the landlord come after you for rent or breach of contract, then you can claim constructive eviction.
But call the fire department first thing tomorrow and get a fire code inspector out as soon as possible to get this official.
I hope you get the relief that you need. Good luck.