Magnitude is sufficient that at least one educated person with access to the data was sufficiently concerned to pull the trigger on an early review. My interpretation of that is that the problem is out of the ordinary in terms of significance.
Discontinue the drug on reaction! Of course, how easy! Problem is that the patient is hypotensive, requiring pressor support or tachycardic requiring cardioversion (these are not hypothetical situations, they happened in the phase 2 trial). I'm an interventionalist in the middle of a case, the last thing I need is a nurse on speakerphone telling me that my other patient is crashing. The devil is in the details and this is exactly the kind of detail that cannot be blown off.