Can a Beer protect me from Dynamite overkill?
You would have to play 3 beers to wind up with 1 bullet if the dynamite blew up on you with 1 bullet left. Here's an example in the rule book for the beer card that explains it...


  Example. You have 2 life points left, and suffer 3 damages from a Dynamite. If you play 2 Beers you will stay alive with 1 life point left (2-3+2), while you would be eliminated playing only one Beer that would allow you to regain just 1 life point. You would still be at zero!