Factual error: In the opening scene for the episode, a character commits suicide by electrocuting themselves with a defibrillator. The device used was an AED (automated external defibrillator) which analyses the electrical rhythm of the heart and only delivers a shock when the heart rhythm is ventricular tachycardia or ventricular fibrillation. In this case, the device would not have delivered a shock as the person did not have both ECG electrodes attached and therefore would not have detected a cardiac rhythm. The person would also have had a normal heart rhythm.
Other mistake: There is no P-trap beneath the red sink in the Madrigal offices.
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm