What can I do if the water in my sink is randomly too hot?

Chances are that it feels really hot but isn't truly dangerously so. Some institutional settings keep it really hot for sanitation purposes, especially if there's a cafeteria or other food service area in the same building. By all means inquire with the head resident, building 'super, or other person with responsibility. But be prepared to get in the habit of turning on the cold water first, then adding hot water as you like.