Doors 1

There are 2 numbered doors :

The 5-numbered door and the 4-numbered door.

[9] abducted [4] and makes [4] and [1] to register their number to the 5-numbered door, and then himself.

419 --> 4 + 1 + 9 = 14 --> 1 + 4 = 5

[9] goes alone to the 5-numbered door. After 81 seconds, [9] died from disobeying the 3-5 persons rule per door.

The remainin persons are :

[1][2][3][4][5][6][7][8]

The plan is :

Plan A

4-numbered door : [3][5][6][8]

3568 --> 3+5+6+8 = 22 --> 2+2 = 4

5-numbered door : [1][2][4][7]

1247 --> 1+2+4+7 = 14 --> 1+4 = 5

There will be an option to change the plan into switching [5] with [1] and [4]:

Plan B

4-numbered door : [3][6][8] [1][4]

3568 --> 3+6+8+1+4 = 22 --> 2+2 = 4

5-numbered door : [1][2][7] [5]

1247 --> 2+7+5 = 14 --> 1+4 = 5

I choose plan B. No one left behind just [9] is dead.