Learn English – What does “vipers” mean here

I sent an email to The Company of Watermen and Lightermen in London and asked them if they knew what a "stinker wharf" was and what it might mean to say that "they made bones" there. Susan Fenwick replied

a stinker wharf would have been a tannery (there were many along the Thames) or perhaps a knackery (where they boiled down animal carcasses to make glue, bone meal, etc) and so called because it smelled bad.

So it seems most likely that he meant something like bone meal when he said "they made bones."

As a side note, "make bones" (in the US anyway) can mean making money, and "bones" can refer to dice or dominoes as well. I don't think either one of those fits here.

I remember this scene vaguely. Phoebe was basically saying she didn't have much time left since she had already gone into labor. What she wanted was for Rachel (or was it Joey?) to ask Frank if she could keep one of the triplets she was having for him (yes I'm a major Friends geek). The question obviously had to be asked as soon as possible.

So basically being "on a clock" in this context means not having much time left for an action to be taken, or being in a hurry, as you said.