All we know is that MSX climbed through their cleared level for reason that they claim they were following a RA on their TCAS.
Chronus, it would appear to me that you do not understand responses to TCAS RAs. If you get a TCAS RA, the "cleared level" goes out the window and you do what is required to follow the RA. If it takes you through the cleared level, then so be it.
While I sympathise with Misd-Agin's comment, his honing in on 700ft is being a bit harsh. There are plenty of variables that could cause the crew to "do well" or "do slow" when responding to an RA. To arbitrarily criticise the crew for taking so long is being a bit harsh at this point.