Relax and prepare myself for the end.
I’m not a theist so I don’t believe in a heaven but maybe a truly calm happily reflective moment to sum up my existence and try to be happy in the feeling that life for others will go on without me and be just fine.
Excellent answer. My own answer was of fun, but in seriousness, if I didn't have any means to tell my family: "I love you", or didn't have the presence of mind to do so, and there was a stranger in front of me, I would also tell him/her about Jesus.