You go, suck it up for your Mom for now, and take pleasure in the fact that they have nothing over you. Thank them when they say they've missed you, tell them you've been living life when they ask where you've been. Be gracious so they won't be able to say how awful you've become since leaving the hall.
And ask Mom for the car keys on the way in "in case she's running late talking to the brother." Or any other excuse you think she'll accept.