No. You may have seen that instruction for some delicate foods like scallops, which can benefit from an ice bath. That's only because searing them can cause overcooking to happen very quickly, so maximizing the temperature difference between the pan and food is important. With tri-tip we're searing for minutes, not seconds. Furthermore, your steak may be cold on the inside if it chills too long, because the sear isn't enough to warm up the middle on a denser food like a tri-tip cut.