void Update()
{
    m_updateTime += Time.deltaTime;
    if (m_updateTime < INTERVAL) return;
    m_updateTime = 0f;

    if (m_onlyOnNoMap && !ZoneSystem.instance.GetGlobalKey(NOMAP_KEY))
    {
        ps.emission.enabled = false;
        return;
    }
    if (Player.m_localPlayer == null || activeEvents.Count == 0)
    {
        ps.emission.enabled = false;
        return;
    }

    var vel = ps.velocityOverLifetime;
    vel.space = ParticleSystemSimulationSpace.World;

    Vector3 best = Vector3.positiveInfinity;
    foreach (var ev in activeEvents)
    {
        Vector3 d = ev.position - Player.m_localPlayer.transform.position;
        if (d.magnitude < best.magnitude) best = d;
    }

    Vector3 dir = best.normalized;
    vel.x = dir.x;
    vel.z = dir.z;

    float t = Mathf.Max(0f, best.magnitude - ev.radius);
    ps.emission.rateOverTimeMultiplier = m_strengthByDistance.Evaluate(t) * m_maxStrength;
    ps.emission.enabled = true;
}