Thank you for your support, Dr. JAREDR!
This a common area of confusion, but it actually is simple (I also had this problem when I was studying for Step 1!!!). Phospholipase C is related to the signal transduction pathway of G-proteins. Thus, PLC is found on the inner side of the cell membrane bilayer and the molecules that activate it have first to interact with a receptor coupled to a G-protein, and more specifically through the Gq pathway (i.e. a1 adrenergic, M1/3/5 muscarinic, 5HT2 serotonergic, H1 histaminic, V1 of ADH).
Gq proteins activate phospholipase C (PLC), which in turn produces diacyl-glycerol (DAG) & inositol triphosphate + calcium (IP3 & Ca2+); DAG & Ca2+ activate protein kinase C (PKC). [--> this is a copy-paste mnemonic from my personal notes for Step 1: C(ue)-(PL)C-C(a2+)-(PK)C].
However, in the present case we have neither a molecule activating the Gq signaling pathway, nor a reference to PLC. On the contrary, the triggering event is the arrest of O2 & energy supply to the myocardial cell, due to blockade of the blood supply. In other words, we have phenomena similar to those observed in the context of rigor mortis. The hallmark of cell death is the release of calcium in the intracellular compartment, because the mechanism that is responsible to put Ca2+ back inside the sarcoplasmic reticulum has been ablated.
I hope this has been made clear!