Most of these problems are solved with good communication
as a SL I'm happy to discuss the LZ with the pilot, if the pilot is not happy with my choice and offers a preferable alternative from his perspective which takes into account his own skill level and the disposition of enemy forces that he is aware of (e.g. where he and the other choppers are taking AA lock) then I'm all for it, even if it means I have to walk a bit.
As a pilot I understand the chopper is my responsibility, I will not be forced to fly somewhere I am not comfortable with, but I always offer an alternative LZ.
Sometimes, particularly in a hot LZ the passengers are not sure if they should get out or if the chopper is going to suddenly lift off, again communication is key, sometimes the SL will order the pilot to abort the drop as the squad will most likely die in that contact or the SL will take the risk and tell his squad to jump. This moment is chaotic, and can go disastrously wrong, it is usually an unexpected situation and therefore is technically an emergency. Really it's best to agree with the pilot before hand if the drop should be aborted in the event of heavy contact with an alternative LZ in mind.
But, no matter what you will get an Orlando Bloom moment at some point there someone got out too slow or too early etc. It's war, and things go wrong
E.g.
You take squad from carrier to LZ, you are 15m off the ground and then take significant fire...
Land - you might die, the squad might die
Abort - you will probably survive, the squad might panic and attempt to jump from too great a height and then die from this or a combination of enemy fire
What went wrong?
Poor intel - landed in unsafe location, perhaps there was a friendly unit nearby you could have landed at and deployed from there. Was the UAV avaliable, was a CAS chopper able to escort?
Poor communication - Could you hear eachother on local? Were the Squad members panicking and talking on radio (Often the latter)
Poor planning - It should have been agreed what to do if engaged
?Poor leadership - It is the SL's responsibility to ensure his men are ready to do what is required, be that dismount or remain in the helo, too often squad members will take the decision upon themselves resulting in some in the chopper and some out. Generally SMs should watch what the SL is doing and do what the SL does (If in doubt, copy the boss)
But the bottom line is that you need to start with good communication, or you are leaving it all up to luck.