Glaring Holes as big as a Giant Glazed Donut

Rating: Null/10 (15 December 2000)

Okay, Here is a ***********SPOILER ALERT
************* I'm warning you!!!
Now, on with the show.
The film really intrigued me. But films can be blown by one small, seemingly insignificant detail that punches a hole in the plot and deflates the entire movie. This is my beef:
At the end, near the airport, Bruce (what you talkin' bout) Willis is given a gun to kill boomer from 'saint elsewhere'. Apparently they want him dead before he releases the virus on the world. (And don't say they didn't give Willis the gun to kill him. What was he going to do, request a sample of the virus at gunpoint, then tell Boomer to 'go about your business'? No.)
Die Hard man dies in his failed attempt. The virus is released. Lo and behold, The insurance lady comes by just in time to save the day. After the virus is released. I guess to get the original virus so they can develop an antidote in the future. Maybe to stop the further spread before Boomer gets off the plane in another country.
So, dear readers, why are they bothering to give (what you talkin' bout) willis a gun to stop boomer at the last possible second? They can go to any time they want. They've done it before. Why not just kill boomer at any time before he takes the virus and be done with it? Run him over with a car on his 18th birthday? Accidental drug overdose while in college? Hey, you've got 40 years to work with, be creative!
Think about it. Would you, wanting to stop a deadly virus from wiping out humanity, place all your bets on a 15 minute window of opportunity while Boomer is in the airport, or any of the 40 years of his life leading up to that point? Did they think viewers wouldn't be able to comprehend one more jump back to a different time, or did they just want to maintain the 'dark' part of their film, at the expense of the logic they themselves have set up?
I've seen comments from fans of this movie that attack anyone who doesn't like it. I wanted to like it, that's why I bought a ticket. The problem is if you get your viewers to suspend disbelief for your movie, you need to give them a set of rules to believe in for the duration of your movie. You can't then suspend the rules you've set up and expect your movie not to have a fatal flaw, and this movie has a big one.