You could do that, yes, but there are a couple issues with it. Firstly, you can't enter the board and exit it the same turn, so you still need to survive at least one turn of return fire. Seeing how the Sunshark isn't substantially tougher than a Crimson Hunter, you really can't take too much return fire. If your enemies don't have skyfire, well then sure, but how often does that really happen these days?
The second issue is that the Sunshark has a lot more guns than just the bomb. By flying away, you waste using those guns. A markerlight, a turret-mounted missile pod, and a pair of seeker missiles are pretty handy. Let's assume the drones have popped off, of course, but even still, this isn't the kind of thing you want to do all the time.
All that said, it's definitely a useful option to keep in mind. If the choice is between 'lose your flyer' or 'bomb somebody and screw out of there', then you could clearly go for option B. If you keep having to do that, though, I'd suggest saving the points and buy yourself a Hammerhead with submunition rounds for a significant discount--it throws large blasts around just about as well and is much tougher overall.