I am not sure if will "explode", or over heat though. I used to do that with no issues. But of course, it depends on how the laptop exhaust the hot air. Some laptops may require the top monitor portion to be left open, e.g. Macbooks and Samsung Chronos 7, as the heat exhaust vents are hidden where the monitor hinge is. Therefore, keeping the monitor part closed will cover the vents.
Anyway, my office often uses docked laptops connected to monitors, mouse and keyboards. Never notice any negative effects so far.