Death

Upon reaching zero health, Warframes will go into a state called Bleedout, which is a twenty-second period of dramatically-reduced combat capability. If the Warframe is not revived during this time, it dies a proper death and must either spend a revive token to continue playing the mission, wait for an ally to finish the mission, or forfeit the mission entirely.

Bleedout

 * Not to be confused with Bleed, the status effect.

Warframes in this state have fallen down to the ground, barely able to shuffle around backwards on their posterior and feet. While bleeding out, Warframes cannot use abilities or perform maneuvers, and can only fire their equipped secondary weapon. Downed Warframes appear as a red diamond on the mini-map and slowly bleed out over 20 seconds.

You can revive these Warframes by holding the action key while nearby and facing them. This action takes priority over most other player input: if you sprint towards the downed ally while holding down the action key, you will automatically stop running and start the revival process (this is immensely useful during Archwing missions, where precise movement is difficult). While being revived, a red diamond will appear to replace the red downed-state bar and begin to fill. Multiple teammates reviving another at the same time speed up the process. Once the revival bar is full, the downed Warframe is revived to full health and shields and may resume using all equipment and powers as normal. Successful revives performed onto other players are tracked by the end-of-mission leaderboard. Tenno downed by The Grustrag Three will be captured by any of their living Carabus Sentinels, and cannot be revived by players while contained.

When reviving an ally in the heat of battle, it's advisable to take care not to be downed yourself. Using crowd-control effects is valuable for safe revival; otherwise, it's very common for players to be downed at the exact moment they've successfully revived a teammate. Sanctuary is a sentinel mod that creates a damage-absorption aura around you while you revive fellows. Shade's Ghost, Loki's Invisibility, and Limbo's Rift Walk all allow you to revive without issue. Also be careful to position yourself not to block your fallen ally's line of sight; sidearms are just as powerful while bleeding out, but they cannot punch through Tenno. A Warframe in bleedout might actually be able to do more damage if they have Provoked equipped, as it amplifies all damage done while bleeding out, including the continuing damage of abilities cast before being downed.

The 20-second bleedout timer can be extended by two effects: Undying Will and Renewal. Undying Will is a Warframe mod which, at max rank, increases bleedout time to 28.4 seconds. Renewal is Oberon's ability which will extend the bleedout timer by 45% before Power Duration effects&mdash;it is possible to cause the bleedout timer to run backwards with enough Power Duration. In both cases, these effects are not reflected in the red bleedout timer text above players' heads; these effects instead increase the amount of time it takes for one second to pass by.

If there are no means for you to be revived (you are playing solo mode, or all other cell members are bleeding out or dead) when you run out of health, you skip the bleedout phase and are immediately dead. Sacrifice, which causes the player's sentinel to prevent Warframe death at the cost of its own life, would have been a highly-desired mod to help solo players do well, but it was an accidental release and can no longer be obtained.

Warframes can also be revived from bleedout by a few special circumstances. The most explicit special case is Nekros's Soul Punch, when augmented with Soul Survivor; it allows for a long-range on-demand revival at an exorbitant energy cost. In addition, if being healed at the moment of hitting 0 HP (by falling down onto a Health Orb, for example), you will nearly-instantly be revived at full health with only a mere interruption to your action at time of death and a message broadcast to all cell members that you were revived. There was a time that Team Heal Restores could revive you, but this was patched out in Update 10.6.2.

Aside from players, there are some NPCs (non-player characters) that have bleedout phases. Kubrows can be revived by any players who find them while they're bleeding out, but though they are marked on the mini-map as a red diamond, there is no center-screen text notification alerting teammates. Rescue targets can be downed while you are escorting them to extraction; they have a bleedout period during which you may take out enemies and safely revive them afterwards. Sentinels cannot be saved from bleedout from all practical standpoint, but on occasion a player might notice the bleedout text and red diamond on the mini-map for a fraction of a second before the sentinel explodes. Enemies do not bleed out at all, although Capture targets writhe around on the ground instead of being turned into a corpse object&mdash;fortunately, they cannot shoot, scoot around, or be revived from that state.

Death
Death occurs after the bleedout timer counts down to 0 seconds. Presumably, your Tenno doesn't actually die&mdash;because there are almost zero permanent consequences for death other than the failure of the mission (if you choose not to revive) and the losses associated with that&mdash;but he or she is simply neutralized as far as the enemy is concerned.

While your Warframe lies dead on the ground, you are able to watch your fellow cell members continue on with the mission, and are given the options to revive your Warframe or abort the mission. If you elect to do neither, you can still complete the mission if another player finishes the objective and makes it to extraction. Be warned that if you have spent more than 2 minutes idle (you cannot be anything but idle while dead on the ground) while the mission is being finished, you do not receive the end-of-mission bonuses like credits, bonus affinity, and alert rewards; you keep in-game pickups and other affinity gained during the mission from activity.

When sentinels die, they might drop loot for you if they have Spare Parts equipped; you can double-dip if they have Regen equipped. On the other hand, if your Kubrow is killed in battle before you are, they lose happiness; if you are killed before your Kubrow, they do not.

Dead enemies, from a technical perspective, are flagged as corpses and are subject to certain mechanics in that state. Most obviously, Nekros can desecrate enemy corpses, treating separated body parts as separate corpses; this leads to players 'desecrating' corpses with damage weapons before the Nekros can use their desecrate ability. Some enemies do not leave corpses, such as Ospreys or the Stalker.

There exist objects in the world that take the form of already-dead enemies, but these corpses are more like lockers (you press the action key to loot them) and do not interact like normal corpses.

Revive Tokens
If they choose to revive, the Warframe spends a Revive Token and will rise up to release an energy blast that deals damage, damaging and knocking over nearby enemies. The Warframe will then be temporarily invulnerable. If you chose to forfeit, you have a chance to reverse your action by pressing and selecting the appropriate option. If a player's teammates are still alive they will enter a spectate mode. Choosing to forfeit allows you to spectate your team making it easier to see if you want to spend a life, which is good if you or your team is not geared enough for the mission.

At 00:00 GMT, each Warframe that a player possesses is restored all its revive tokens. No more than 4 revive tokens can be held per Warframe at a time, excluding new players in Vor's Prize, who start with 12 revives. More revive tokens can be purchased at 3 per token by navigating to the arsenal, under the Warframe selector.

When using a revive token, dead companions come back to life. Some players intentionally die and revive via token in order to bring back their companions for their useful long-term utility.

Bugs

 * Movement can prove to be cumbersome during Bleedout. Shuffling backwards doesn't always respond properly, and you can easily get caught on strange terrain.
 * If all living teammates make it to the extraction zone while a player elsewhere bleeds to death, the living must step out of the extraction zone and back to trigger the extraction sequence and the end of the mission.