For an office envoronment I would get food that does not require cooking. It's not like you'll be stranded there for months. An unopened jar of peanut butter and a sealed package of saltine crackers should do it.

From a recent camping trip, I can comment on Sterno vs. alcohol (in a Trangia burner). No contest what-so-ever! The Trangia/alcohol stove smacked the Sterno down hard. We were cooking fondue (I know you're now wondering - what kind of camping trip was THAT?!) With Sterno, we couldn't keep the oil hot enough to cook the meat on the little pronged forks. We had to keep running inside the trailer and reheating the oil on the stove in there. I switched over to the Trangia and it kept the oil at a rolling boil forever. And it was a full rolling boil - you had to put your little meat thingies in there carefully because the oil was so hot it almost climbed out of the pot when the food was introduced.