A Client is an ordered sequence of OperationContexts, at most one of which is currently active. Developers are allowed to rely on the assumption that an OperationContext will only be current on a Client for one contiguous interval of time. AlternativeOpCtx violates this design and may cause issue for interruptibility and currentOp reporting.
 
Instead, AlternativeClientRegion should be used to start a new Client to do the job.