I get where you're coming from, but is it really that hard to find a tall building?
All joking aside, the problem I have is that it's a slippery slope. You can make assisted suicide legal *only* in cases where you're 100% sure the person is in a normal, logical state of mind when they decide. That could easily eventually turn into allowing it whenever they're cleared by any doctor/psychologist. That could easily turn into allowing it whenever they're cleared by family and friends. Pretty soon, you're killing people who are simply bi-polar or whacked out on meds. Once you cross the line, you'll have people fighting to push it farther and farther. Look at Replay in professional sports.
The "it's my body, I choose when to die!!1!" argument doesn't hold as much water if you're hopped up on crazy pills and don't even really know where you are.