Brake issue

I have a 2008 Ford Escape AWD that the brakes went out on almost 4 weeks ago (I had a little brake when I pumped them up). I've been waiting on my mechanic to come fix them but he's been "busy". My brake fluid still looks full so I went out the other day to see if I could pump up my brakes still yet to drive it to a shop to get fixed and as I pushed in the brake pedal there was a single thump, which sounded like it was under the hood, everytime I pushed it in. My car was in park so was not moving. What could the thump be and would it be safe to drive 15 miles to a shop?

Absolutely not.