Feeling Down?
When Injury plus Complications exceeds your base Level, you're Down. This doesn't necessarily mean unconscious, but you can't act meaningfully in the scene any more. The only rolls you can make are passive resistance - no more charging into battle or casting spells until you recover enough to get up and about. If the GM allows any actions besides that, it must be Free Actions. Note that in some cases, Down merely indicates a loss of agency - the character might have been charmed, and forced to run away.
You stay Down until your total harm drops below your Level again.
Staggered
If that's too restrictive for your preferred style of play, keep going! You can keep taking turns until you simply have no positive EL left. At that point, you are definitely Down.
Until then, as long as you can keep making rolls with positive results the GM might let you keep struggling, but any time you completely fail to achieve any positive effect for two consecutive turns you have to make a resistance roll against your current Harm to stay conscious.
Yes, this means positive EL in ANY Role counts toward staying awake enough to at least call out advice to your teammates!