Factual error: Every time we see Leonard's laser lab the door is open and he is able, if the story requires it, to fire the laser. As evidenced by the several safety notices visible and the scripted requirements for characters to put on safety goggles it should not be possible to activate the laser while the lab door is open - it would be interlocked, meaning the laser wouldn't function unless the door is closed.
LordKelvin
3rd Aug 2019