Given the value of the whole package (which is over $110M Mallinckrodt willing to pay), it's clear that Ocera is worth much higher than the current share price. So even the deal was not falling through, I don't think OCRX share price will fall below the current level.
No chance of the "investigation" by Tripp Levy derailing the merger. Nuisance lawsuits are a part of all deals and are settled or dismissed before most closings.
No extra financial award for shareholders - just a a filing with more disclosure and, most importantly, an agreement to pay the plaintiff's attorneys. The last thing the suing firms want is for the deal to be killed!
Good business if you can get it - you can see why they spam internet newsgroups to drum up business.