We shouldn't get large dts anymore (the time sync code has been fixed).

I think this code is written so that the arm animation always finishes (or, at least, that's a side effect of how it's written). However, it also means that the arm animation might stop in between iterations for a couple frames (depending on the timing between server messages), which can add a bit of choppyness, but really not a big deal until we have smoothing of entities implemented (since they are super jerky already).