Why didn't they catch any of their fallen comrades? They just stood there

I think its because they are far away and also because they are not permitted to "interfere"

Time to prepare more graves - ah screw it, a whole cemetery is waiting ahead XD

Wish they upgrade show to RTX4090 Mc looks Epic in Manhua

I wonder why didn't mc challenge them

mc is very smart and calculating. This match is explained better in the novel but even then its fairly complicated. You will see more as it progresses and understand what mc is doing. Also remember, mc cultivation is lower than most of the top geniuses here. He can't stand up there and just continuously accept all challenges from his enemies within all of the other 9 departments. Its only once enough of the strong enemies have already been eliminated by loss or by winning a place in the secret realm and are therefore now out of the competition...only then will he have a chance. If the Chiefs of several other Divisions tell their students to challenge Tan Yun, then they will have to do so.