Do not fall into the pit, and if you do: do not pull the lever. When the three-hundred metric tonne dormant golem “LORD SLABATHOR” comes crashing down he’s not getting up again. There is little that could save you from spending eternity in this dark tomb.
This is a one-time trap, and you need to a be a special kind of stupid to trigger the full severity of it. How curious are your players?