During some major Jin Ying fight scenes, it has been illustrated that fighters manually protect themselves by coating a layer of internal energy around their body, such that 3rd party outsiders cannot interfere with the fight. Examples include:
HSDS chapter 31:
左手一挥,又有三名好手上前夹攻。张无忌和玄冥二老此时各运神功,数丈方圆之内劲风如刀,那三名好手怎能插得下手去?
HSDS chapter 38:
周颠将狗腿往前一送,刚碰到渡厄口唇,突然间手臂一震,半身酸麻,啪的一声,狗腿掉在地上。原来渡厄此时内劲布满全身,已至“蝇虫不能落”的境界,四肢百骸一遇外力相加,立时反弹出来。
BXJ chapter 20:
孙仲君怒道:“别管我。我跟贼道拚了。”梅剑和道:“贼道已知小师叔的厉害,正用最上乘剑法护住了全身,你上去是白送性命。”孙仲君用力甩脱他手,叫道:“我不管,我去帮师叔。”她以前恼恨袁承志,从来不提“ 师叔”两字,这时见他与恶道为敌,竟然于顷刻间宿怨尽消。梅剑和道:“那你发一件暗器试试!”孙仲君取出金 镖,运劲往玉真子背后掷去。玉真子全神凝视袁承志的剑尖,金镖飞来,犹如未觉。孙仲君正喜得手,突听当的一 声,梅剑和失声大叫:“不好!”抱住她身子往下便倒。孙仲君刚扑下地,只见刚才发出的金镖镖尖已射向自己胸 前,全没看清那恶道如何会把镖激打回来,其时已不及闪避抵挡,只有睁目待死
In the above cases, if a 3rd party actually interfered, they would be killed by the manual-protect on the spot.
However, there is also the opposite case where the fighter involved is completely helpless to 3rd party interference:
DGSD chapter 40
虚竹自幼在本寺长大,下山半年,却不知从何处学了这一身惊人技艺回来,又见他抓住敌人,并不能制敌,但鸠摩 智每一掌中都含着摧筋断骨、震破内家真气的大威力,只要给击中了一下,非气绝身亡不可。此刻少林众僧中,不论哪一个出手相助,只须轻轻一指,都能取了鸠摩智的性命,但这番相斗,并非志在杀了对方,而是为了维护少林一派的声誉,若有人上前杀了鸠摩智,只有大损少林派令誉 。
Can anyone think of an explanation?