i think something along these lines could work...maybe during their fight Anakin is in a position to kill Obi-wan and as his last escape the only move he can make ends up knocking Anakin into the lava...well not directly...he's like hanging on the edge saberless (not trying to make this all like the Maul fight). Anakin then does that cliche bad guy, oh no, dont let me die thing...obi wan trys to help him, maybe gets pulled down and is also hanging from some edge...they struggle and anakin mainly just trying to pull obi wan down not really seeming to care for his own saftey. Obi-wan manages to fend him off, but in the process knocks anakin into the lava...maybe have anakin just give one of those creepy evil smiles he has as he falls (or yell "I'll be back"
)I dunno, think im mixing a few ideas, cause one was that when obi-wan offers to help and tells anakin he can be forgiven and repent and all that crapola, anakin just kinda reaches up his hand like he's gonna take it then lets go and falls in...then giving the evil (knowing) smile as he falls. I dunno...just really rough ideas.
As far Han/Lando and the falcon...something like that could work, but i think it should be something more underhanded...not a threat...like maybe a game of sabaac (i think thats the 'poker' game they play in star wars). fully legit game, so there are impartial third parties..maybe even a judge. Stakes get high, Lando is loosing maybe basically on his last hand, has a killer hand but no money to bet on it so he wagers the falcon knowing he cant loose (he has like the second best hand in the game) Han accepts and when they show their cards Han has the best hand or something...beats him buy like the poker equivelant of. Lando knows Han cheated (which he did) but it cant be proved...know one actually saw anything and the official calls it a fair play...Lando is now bitter about loosing the falcon.
-Darth Simon