In Orberg LLPSI:
…nam sicut ille mirum in modum servatus est.
= …nam sicut ille servatus est in modum mirum.
‘Mirum’ adiectivum masculinum accusativum (?)
Ita est, ut dicis, pmda.
nam sicut ille mirum in modum servatus est, cum iam de salute desperaret, ita homines nonnumquam conta spem e maximis periculis eripiuntur.
…actually revisiting this on my quick review of LLPSI Pars I, it seems that ‘mirum’ must qualify ‘modum’ and, therefore, must be neuter accusative singular.
I translate it as follows: For just as he was saved in this surprising way, when he had already despaired of life, not a few men have against hope been rescued in this way from the greatest danger’.
No, modus is masculine 
oops.. Of course… The longer I study the less I know.
But it is qualified in the accusative masculine by ‘mirum’ right?
Yep!
We all slip from time to time. The longer we study, the more pebbles on the hill to trip us up.