Past / Present -Story Telling

Scenario: I'm talking about a movie.

1. The movie talks about firefighers and this guy in this movie is stuck inside this building with a fire. The floor collapsed and he fell down there and now he is down there and his whole life flashes back at him. Showing how his past life was, his best friend died, co-worker got injured, and now it's his turn to die. (If this is not okay, why? I don't have to use all present tense when telling a story right? I need to use past and present to show the transition in time?)

For eg.:
http://owl.english.purdue.edu/handouts/grammar/g_tensec.html

A dragonfly rests on a branch overhanging a small stream this July morning. It is newly emerged from brown nymphal skin. As a nymph, it crept over the rocks of the stream bottom, feeding first on protozoa and mites, then, as it grew larger, on the young of other aquatic insects. Now an adult, it will feed on flying insects and eventually will mate. The mature dragonfly is completely transformed from the drab creature that once blended with underwater sticks and leaves. Its head, thorax, and abdomen glitter; its wings are iridescent in the sunlight. (adapted from an article in the magazine Wilderness)

This writer uses the present tense to describe the appearance of a dragonfly on a particular July morning. However, both past and future tenses are called for when she refers to its previous actions and to its predictable activity in the future.

The above paragraph is okay? But #1 is not? I can't use tenses like that in #1 to show previous actions? For #1, why can't I show shifts in time like that? What makes the paragraph above to be okay but not #1?

I can't see why #1 is wrong, could you give me some examples? Also, it sounds kind of awkward when I use all present tense, or maybe I'm not used to it? I hear a lot of people do this too, even writers.

http://sympaticomsn.ctv.ca/servlet/ArticleNews/story/CTVNews/1110504783273_105913983?hub=Canada

But that city isn't alone. The website GasTips.com shows that residents of Moose Factory, Ont. were paying up to $1.15 a litre earlier this week.

(They have past and present tenses here? How come #1 can't be like this?


Thanks.