Weep holes in UPVC doors - no way through?

Hi all,

The bottom rail of my UPVC doors has filled up with water and leaked inwards with the wind and rain we've had of late. There are two small holes in the inner cill, and two larger holes in the outside of the frame. The outer holes are about 15mm lower and 30mm horizontally offset from the inner holes. The outer holes are also not at the bottom of the chamber, so i don't see how the frame could ever drain fully anyway, although i don't think that's the main issue...

No water comes out the outer holes when I pour water into the cill. I have shone a strong light into the outer hole, and I don't see it through the inner hole. It also seems there is a separating horizontal element between the inner and outer holes inside the frame, like an internal 'floor'. So, I suspect it is possible that either there is no hole in this 'floor' connecting the two holes, or there is, but it is blocked and inaccessible.

My question is, is there any issue with me just drilling straight through the inner hole and down through the 'floor' thing so that the inner and outer holes can link up?

I don't know anything about door frames, presumably there is a reason why weep holes are generally offset, and presumably every element within the frame does a job. Am I going to break the whole thing by drilling through it??!

Couple of pics attached.

Any advice welcome.