> self waitOk: [ ".... working code .." ] ensureAfter: [ "This block
> will be evaluated only if we entered working block and regardless
> after it terminated or finished in regular way"  ]
>

ohh.. yet again, there's no guarantees that code:

self waitOk: [ ".... working code .." ] ensureAfter: [ self signal ]

will exit with signalled state, because you can terminate process
after entering the ensureAfter block, but before sending #signal
message.

Then the only way is to make it to handle all by VM. And #critical:
code should look simply like:

critical: mutuallyExcludedBlock

   self waitThenEvaluateAndSignalAfter: mutuallyExcludedBlock


-- 
Best regards,
Igor Stasenko AKA sig.