If you try something enough times, you're sure to succeed. This is the rationale behind the take-20 rule in the 3rd edition of Dungeons & Dragons: If you are not in a stressful situation (e.g. combat, or fleeing pursuit), you can assume that you take your time on a skill and make multiple attempts, until you manage to achieve a success. For example, if a single attempt at picking a lock takes 1 minute of time, then you can spend 20 minutes to proceed very carefully, and - if you had any chance at all of rolling a success on a normal skill check - assume that you succeed.
The obvious corollary to this is that if you try something enough times, you're sure to fail spectacularly.
[Reminder: Our guest commentators have not seen Rogue One. Part of the fun is seeing how their untainted impressions re-interpret the movie through the lens of our comic.]
Stealth missions work best when everyone actually wants to be stealthy.
I'll bring up the leadership point again here because anything bad that happens after this is officially Cassian's fault. A good leader would have realised that the trigger-happy droid who doesn't even understand the concept of stealth should probably not be flying the ship, and instead, the team member obsessed with stealthy non-violence - who is an actual pilot - should be piloting the ship.
Seriously, K-2 is just being K-2 here. Cassian should have expected this. He's lucky that between K-2 and Chirrut-Baze, they probably can take on an Imperial weapons facility in a frontal assault.
Everything I just said about making plans, being organized, and having an actual stealth squad separate from the distraction squad?
Cassian: We don't need to steal a ship. We have a perfectly viable, functioning ship right now.
Bodhi: Why are you flying so low? Fly higher!
K-2SO: We're avoiding radar.
Cassian: Good idea. Be careful in this weather.
K-2SO: Also: flying low and dodging the crags is fun!
GM: Make a Piloting roll, Sally.
GM: Okay, you're good.
K-2SO: I'm going in closer to one of the big ones.
K-2SO: Hmmm, even closer! Ooops, 2!
K-2SO: Oh fiddlesticks. So much for stealth! I guess we have to go kill Krennic and steal an Imperial gunship now.