Microwave dilemma at work

I have always brought my lunch to work and love it! However, I got a new job where the microwave is in a super inconvenient location. This means I have to heat up my food and carry it back to my desk or closest break room, which is quite a distance. That in itself isn’t a huge deal except I don’t know how to carry the hot food back... I have reusable plastic and glass containers. Yesterday I put my warmed up spaghetti glass container back in my lunchbox to carry it back but it slightly melted the inside of the bag by the time I got to my desk. Any suggestions of how to transport hot food? I’m going to try to implement more cold recipes but nothing beats a hot lunch. Maybe there’s a fabric material bag I can keep at my desk just to carry the food? What’s would you recommend? Everyone I sit by goes to the lobby cafeteria to eat, hence why microwaves are scarce here. No one really uses them.