Easy to comment on videos.....but this is another example of stupid flying....totally unneccessary...
The tail is already drawing water....with the pilot probably being unaware of the risk or situation in general..
The fenestron turns at around 5500 rpm....and is able to suck water sprayed up from the downwash, reducing the effect of the tail rotor significantly.....and especially in this phase of the flight (slow speed) the risk of loss of tailrotor effectiveness is quiet high
..