Even if your life is in danger, you should avoid negative karma, because it is just one life and we have many future lives to consider. In fact, to purify ourselves, we should be ready to sacrifice this life to avoid any bad karma. There will be many lives after this one. So, creating bad karma and getting bad accumulations will cause us problems for hundreds of thousands of future lives. This life is very short and can be sacrificed for that big purpose. Saying this life is short and future lives long is true. How long are we going to stay here? By now, maybe one-half of our life is already wasted or already gone. Perhaps only one quarter of our life is left, that too is short. But the next life is long and how many lives will there be until enlightenment? It is endless. There will be no end of your taking rebirths. Rather than worrying about this short life, think about the impact of negative accumulations on future lives.
For the sake of the mundane comfort and successes in this life, we unfortunately engage in all sorts of negative deeds. To get a nicer home, to get more money, to have more pleasure or a more pleasant way of living, we normally do all sorts of bad things. But if we think about it clearly, we may realise this is very stupid. We are all looking for happiness and for this kind of short-term happiness, we accumulate so much of negative karma for us to suffer throughout many future lifetimes.
For example, we are making money so that we will be happy. We are keeping ourselves busy running around for happiness. Not only us, even the ants keep themselves busy going everywhere, looking endlessly for something. The same is true for butterflies and mosquitoes. All sentient beings, like us, are busy. Desiring happiness, we keep ourselves busy. Mosquitoes are busy because they want to be happy. They want to eat so they hang around and bite us just to survive. That is how we survive in this world. Though it is quite stupid from the point of view of the spiritual path, it makes sense from the mundane point of view. It is stupid, because this life is so short and the future lives are countless.
Happiness is like dew on the grass, it disappears in a few seconds. When the sun comes out, the dew disappears immediately. As soon as you get some sense of happiness, it is over. As soon as you get some sense of pleasure, it too disappears. This is our typical experience. We waste a lot of time and energy to gain what will soon pass. I do not know if this is true for you but this is my own experience. I like good things and I like pleasure but they all seem over too soon. It is like chasing a rainbow, which is there for a few seconds then disappears, somewhere, somehow. It definitely cannot and does not remain forever. That is certain.
We need to be intelligent about this life. To practise the Bodhisattva path, it is important to understand the universal law of karma. Should we give importance to this life and accumulate a lot of bad karma or should we think of the hundreds of lives to come and strictly abandon accumulating it? To understand this, we must genuinely and sincerely practise the spiritual path.