Assuming this is the sliding-block-puzzle room (the one with the block in it)... You just fall right through! There are multiple pits "underneath" which lead back into that same room from a different angle. You use your own gravity to move the block to the button! I suspect I didn't exactly telegraph this process well enough, though...
Generally, hopefully, you can't get stuck. I checked all over the place for weird softlocks and wasn't happy with the layouts until I couldn't find any more. Falling into a pit is almost always progress to a checkpoint!