And then I noticed by the exit, there was an old entry to the service elevator that was cemented over but the old up/down buttons are still there.I've taken a lot of cool pictures of various items.

You didn't sign anything with them.Honestly, If this were me and I was stuck in a ridiculous lease like that, I would fill that washer with cement like on Seinfeld.

It's hard to tell if it's epoxy or hydraulic cement or just a skim coat.

We have used tile (works best on a cement pad); an overlay decking that comes in squares like tile and rubber mats over painted deck.We inherited artificial turf ... didn't really care for it.  

I'm wondering if there is any type of bonding cement/sealant I could use to patch the leak as opposed to having to replacing the piping or even cutting off the pipe and capping it.

From tiles (floor, ceiling, walls) to insulation, to paint, cement, siding  and sheetrock/plaster to name a few.

You also see it in cement board siding. 

There is a quality fiber cement product to replace if needed.

Electrical/plumbing/shower cement board & vapor barrier.....

Had to do some exterior cement work so rest of the exterior will be buttoned up in 2 weeks.