drilling 4" hole through brick

[dal]

Hi all, I'm going to be fitting a online fan in the loft to extract from my bathroom, this will involve drilling through a brick wall. As this would mean drilling whilst up a ladder im thinking of drilling from inside the loft. Would doing this give me a clean exit hole on the outside or would it blow the brick like a normal drill would.

Thanks

 

[dal]

Cheers guys.

I take it I should drill at a slight upwards angle to avoid rain running in
Also would it matter if my pilot hole was a bit bigger than the guide drill on the core cutter

 

[dal]

cheers guys. Would it be ok if the pilot hole that I drill all the way through the wall first is slightly bigger than the guide bit for the core cutter as mine is 10mm and I think the guide bit is a bit smaller.