Life is full of surprises. You don't know what life throws at you any moment. And quite obviously plans and surprises don't go hand in hand (unless you're planning a surprise). So it may so happen that something ends before you expected it to, or your plans are shattered unexpectedly. For something such may happen, don't lose hope, just cling on and don't be afraid. Continue moving as long as you're alive. But yes, never initiate an unplanned exit, which is to be simply read as NEVER QUIT.