purple linckis starfish dying?

I purchased a purple linckia starfish from liveaquaria this week. This is the first time I've attempted an online order rather than purchasing from a LFS. My tank is a well established reef with stable parameters. I used the drip method acclimation over the course of an hour before releasing into the tank. The starfish did great the first day moving all over the rock work and appearing healthy and well adjusted. However by day 3 I began to see a white substance exuding from one of its legs at the base of the body. By the end of day 3 I found the starfish upside down on the bottom of the tank. I netted it up and realized it detached the leg that had been producing the white substance. I thought it was dead but then noticed the feelers on the bottom of the remaining legs were still moving. I placed it on a rock which it attached to. The detached leg at the bottom of the tank also seemed to have moved and just in case this was an attempt at reproduction I left the leg segment down in the rocks. The starfish has moved along the rocks this evening but is now slowly peeling away with legs hanging limp and mouth exposed looking as if it may fall from the rock it's attached to. So now my question. Do I leave it in the tank? If it dies overnight will it pollute my tank and kill my corals? What about the leg segment that detached, should I remove it?