I was assisting a team from Digital (DEC) recommissioning a VAX 11/750 system in our computer room. The DEC guys forgot to lower the feet on the disk unit and when the disk pack confidence test started, the whole unit lurched forward and two of us had to hold it down so it didn't damage any of its ribbon cables.

Later, when the DEC guys were pushing the unit back in to place, one of the ribbon cables got caught between two metal edges and was cut in half. Fortunately, we had a spare.