Taking a dump. Didn't some king or other get offed while doing that?
Eglon was killed and his servants thought he was taking a dump.
Judges 3:22-24
22 Even the handle sank in, and the blade came out his back. The king’s fat covered the whole sword, so Ehud left the sword in Eglon. 23 Then he went out of the room and closed and locked the doors behind him. 24 When the servants returned just after Ehud left, they found the doors to the room locked. So they thought the king was relieving himself.