I’m almost sure that this is not the smartest move, but the whole point of me going out of the house was to find my roommate, who’s not particularly good at survival skills and was stuck in his/her car.
A few hours ago, I might have died by choosing to stay in my own car, and even if I chose to keep one window open and periodically turn the truck on for warmth, I had a full tank and plenty of blankets. My roommate might have had neither when he/she got stuck. Finding him/her (was the gender ever specified?!) alive today would be a miracle. Tomorrow morning... improbable.
If help is on its way for him/her, then trying to move towards him/her would take me closer to help, as well. Also, moving I might find help or other people on the way. And I can still dig in half an hour, if I don’t seem able to orient myself or get very far.
Also, I’m guessing a flare would be more effective at night.