You can get this playing solo with two controllers if you don't mind doing some joypad juggling. Sign in with another account (or as a guest) with a second controller and play through one of the main tombs (I did the Tomb of the Timekeeper). Some parts require briefly using both controllers at the same time or quickly alternating between the two.
To make sure you get the most deaths you may need to deliberately kill yourself a few times. Just jump off an edge after you hit a checkpoint and you can respawn next to your other character. You can see the total number of deaths for each character in the stats that cycle round at the end of the level.