Stun OK, interrupt no. Good operatives do not rely on big heals to stay up.
Even if you stun the hell outta him, if you do it early he will roflchopper at your face when he gets outa stun with 30% hp and proceed to spam his thing. If you want to keep your stun until he reaches 30%, well good luck taking a good operative to 30% without stunning him. Its a catch-22.
PS: Xerain is the most clueless players ive ever saw, and once i got into a WZ with him i loled even more because he cant touch me, imagine a good geared healing OP. Clueless FOTM wannabe PvP hero is clueless.
Smash places alot of pressure on guard. Root and snare the tank and pull the healer. Sin tanks closing is not as good as leap. Roots and snares and interrupts. Don't fill the resolve. Something helpful.