That's kinda the point, in this situation you can't. He needs to be in state 5150 for the round to finish. That means you can't custom state him. I suppose you could try custom stating him into your own 5150 and turning off camera movement in your states, that might work, i have never tested it.
Thing is, if you turn it off there, the camera is going to center on p2 regardless of who it is, that will mean your character gives everyone else the effect you want forever, but you don't necessarily manage to apply it to them.
If you were happy to say... make p2 explode so he had no body this would be doable. Or if you were OK with p2 teleporting, or if you wanted your character to jump to the middle of the screen.
Anything that would require p2 being able to actually move OFFSCREEN while still being visible is somewhat impossible...
Actually, i'm going to explain this but it's awkward and you may not get it.
Make sure your winstate has movetype = A, then do the following in the winstate itself.
[State targetstate]
type = targetstate
trigger1 = winko && p2stateno = 5150
value = some number, whatever, you pick
persistent = 0
inside that some number here are the important bits
[State Explod]
type = explod
trigger1 = time = 0
anim = 5150
removetime = -1
bindtime = 1
[state Posadd]
type = posadd
trigger1 = time = 0
x = floor(p2dist X)
y = 200
[state Selfstate]
type = selfstate
trigger1 = time = 0
value = 5150
What this will do is leave behind an explod of a required animation, in this case, death. It is not bound with p2 so it'll stay in place. P2 then teleports himself to you, and underneath you so he is offscreen. You can then use movecamera as much as you wish, p2 will be in your spot so whatever you do you'll be able to center
This is not likely to make much sense.
D-Day