As you enter the puzzle room, shoot 2 bats that flutter toward you from the back of the room.

Go around behind the scales and stand in the shallow pool.

Select the SMALL WATERSKIN from your inventory and press Action...

...to fill it with water.

Return to the front of the scales, step up onto the low platform and position Lara in front of the scale with the water symbol.

Select the filled waterskin from your inventory...

...to pour water into the scale.

Next, position Lara in front of the scale with the sun symbol. Select the JERRYCAN from your inventory to pour gasoline into the scale.

Go back through the LIONS' HEADS room to get the WOODEN TORCH from where you dropped it.

Light it on one of the flaming torches.

Then climb up to the middle scale and use the torch to ignite the gasoline.

Finally, position Lara in front of the scale with the pyramid symbol. Select the BAG OF SAND from your inventory to pour sand into the scale.

After filling all three scales correctly, the door to the left (west) opens. Enter to get the attention of the 2 mummies inside. Then back out...

...wait for them to come to the doorway, and destroy them both with a single grenade or explosive arrow.

Re-enter the room and use the CROWBAR to pry the NORTHERN SHAFT KEY off the wall. When you do, the east door in the SCALE ROOM opens.

Go through the SCALE ROOM into the EAST ROOM.

Pick up poisoned arrows and revolver ammo on either side of the entrance ramp.

There are 3 more lion heads with gems in their mouths, but the exit is already open so you don't need to shoot them. Start up the stairs to the east...

...and kill the 2 dogs that charge down toward you. Then continue up the stairs.

[Mastabas Walkthrough]