imma walk through it, because it's worse than you think. :)
so he tips backward, suddenly unable to feel his legs...
obi-wan is just standing there, staring, the fury on his face fading to grief as he realizes that maul is finished, but qui-gon's still dead. maul leaves that scene behind like a meteor. (for parsing his expression, it helps to cover up his brow tattoos and just look at the rest of his face.)
down he goes... falling what looks like 17+ stories into the coolant reservoir at the bottom of the shaft.
that is a long ass drop. if i've done my math right, maul fell for at least 3.4 seconds, reaching a velocity of 72 mph (116 kph).
in the comics, it appears he was awake and together enough to use the force to slow himself before hitting the coolant at the bottom. force users bounce well, but yeesh. that might have been splat and roll credits if he wasn't still fighting.
we don't know how long he was down there for. reactors use coolants for a long time, because shutting the system down to flush them is expensive. down time is credits, eh? however long it was, minutes or days, it seems he couldn't climb out in time. the coolant was flushed, and maul went through whatever series of tubes, pipes, valves, and fluid junctions to be drained into a plastisteel containment tube.
at this point... there's no air. however long it was, he had no food, questionably drinkable liquid, and a digestive system that ended abruptly with cauterization. he's trapped, with half his saber and seemingly not enough strength to escape while still on naboo.
then his tube was loaded up onto a trash barge by some automated system that didn't notice or care that there was a person in there, and the ship took off.
naboo is five hyperlane changes and eight sectors away from lotho minor. in a fast ship or a snazzy military vessel with a 1.0 hyperdrive that's a few days journey. two or three maybe. but maul wasn't in a cabin on a pleasure cruiser, he was in a space-cold transparisteel tube, on a trash barge. that thing probably had a 3.0 or 2.5 hyperdrive, more concerned with fuel efficiency than speed. he likely spent a week or more like that, possibly frozen, with no idea where he was going.
the ship doesn't even land. the reactor fluid tubes and maul are just dropped from the sky on a fly by. the tubes don't break either. they crash down, the fluid presumably begins to thaw. he wakes (?) up to air and light on the other side of a transparisteel wall. maul didn't cut it open with his saber hilt either. no, he apparently just punched through, still pissed off and still determined to live.
there's speculation that darth maul either knows morichro, is just straight up a zombie, or is maybe a ghost possessing himself. how else could he have survived all this?