Drop Ceiling Carrying Current?
Switching just the 2 apartment's breakers off was a good try, but now you need to switch other breakers until the current is gone. Then, leave that circuit off even if someone needs to run an extension cord or 2 until the repair is completed.

Once it's gone, then nails can be extracted &amp; reinserted until the offender is found in the ceiling &amp; walls, the token (hopefully) long nail or screw would be the likely culprit. If the Landlord doesn't act immediately &amp; filing a complaint with Local Officials has an estimate of weeks, months, a year or never.

Then, you can still protect yourselves by insulating the drop's grid, perimeter rail ends &amp; bottoms &amp; the hanging wires. Rails with, bicycle inner tube chunks, plastic L's like the clear clips that come with mini-blinds to secure the blind's bottom (stores sell them in bulk packs), or anything similar in shape &amp; material. Hanging wires can be removed &amp; wrapped with electrical tape &amp; reinstalled or at the ceiling you may be able to slip on small rubber tubes.