[Avodah] Parsha question: Umazeh mei haniddah yechabeis begadav..

[SBA]

Hands up those who know all about the Parah Adumah and its effect,
ie,'letaher temeim uletamei tehorim'?

Everyone! Excellent.

And how many of us know that the person who shpritzes the 'eifer parah' on
the tamei, he himself then becomes tamei?

If the percentages are the same all over, then I would say that 90% are
replying "I do".

Why am I mentioning all this?

Oydeh ve'eivosh, until yesterday I too thought so. 
Until a melamed here, who also somehow just realised that it is actually not
so at all, mentioned it to me.

It's a befeirush Rashi, just after Sheni this week (19:21: 
"Umazeh mei hanidah": 'Omru Raboseinu, shehamazeh tahor' (ayen shom)

(No doubt all DY learners remember this from Yuma 14.)

SBA