Ever gone into the clockworks only to realize that your shield isn't equipped, or that all your weapon slots are not filled up? I have and it has caused me to die more than I would have.
Solution: When you walk onto a lift a warning pops up reading: Your shield is not equipped/you have open weapon slots do you wish to continue? y/n
effectively giving you the opportunity to go back and quickly equip the said items without blocking those who do it on purpose.
~Gigglebytes
On most floors, excluding boss floors after the first, there is a loadout station at the beginning of the floor. Keeping yourself equipped is your own responsibility.