(TL;DR version at bottom)
I briefly mentioned fleeing and how it affects the flow of the game in another thread, quickly got carried away, and then remembered that the topic of the thread was Astrogation checks. I figured I have enough to say about it that maybe someone out there will care to listen.
Think of how many times in the original Star Wars trilogy that the characters are seen fleeing from something. Fleeing from Mos Eisley Spaceport, fleeing from the the detention block on the Death Star, fleeing from the Death Star itself, fleeing from the wampa's lair, fleeing from Echo Base, fleeing from Cloud City, fleeing from the Pit of Carkoon, fleeing from the exploding Death Star II, etc., etc. Imagine that if instead of fleeing from all these situations, the characters stood around and obliterated every last stormtrooper or thug or whatever and then casually walked around to loot all the bodies.
When I GM, I love putting my players in situations where they simply cannot blast their way to safety. Putting them against opponents that have them beat in both firepower and numbers is much more thrilling, in my opinion, then putting them against a group of enemies with which they are evenly matched. I do put them up against groups that they can defeat. In fact, I probably do this about as often as any other GM. But I love throwing them in situations where they need to flee, allowing them to barely escape with their lives. This conditions the players and alters their way of thinking, forcing them to look at situations for a moment and weigh the odds instead of charging in with swords (or blasters) drawn.
Too many RPGs, whether they be played on the table or on a screen, have fallen into the pattern of placing the player in a situation, requiring the player to completely defeat all challenges the situation creates, and then allowing the player to move forward to repeat the process. This is a staple that I use to see back when I played D&D for a number of different GMs. Every situation required players to completely eradicate any enemies in the area before they could see any progress. This seems to be the recipe for the basic dungeon crawl.
A game like the Star Wars RPG that FFG has created does not need to be played in this way. It can be non-linear and fluid. This requires the GM to have a bit of skill and the ability to adapt, but it allows many more possibilities for the players.
TL;DR/Closing Statement: Don't be afraid to throw players into situations that they cannot overcome by firepower alone. Make things hard, impossible even, and have a plan for when they retreat. If done correctly, they won't complain about not being able to kill every last baddie, but will relish in the fact that they managed to escape unbeatable odds with their lives.