I've done some experiments for this purpose...
I moved a Lanius into a full-oxygen room with a human, at at the same moment, moved an Engi into the no-oxygen room the Lanius had just occupied. When the human started taking damage, I paused and checked the results.
- With level 1 oxygen, the Engi had 8 health then I paused, and the human had 97
- With oxygen unpowered, the engi had 31 health when I paused, and the human had 97
With level 3 oxygen, the lanius was not able to drain the room, although he could at level 2 oxygen. 2 Lanius was enough to drain a room at level 3 oxygen, and oddly enough, at level 3 oxygen, 2 lanius in connected rooms could drain both rooms when the door was open, but couldn't drain either room when the door was shut. Air draining from rooms doesn't follow the simple formula of "air is drained from each room individually, and air filters between rooms through doorways"; open doorways seem to actually enhance a Lanius's air-draining abilities.
To establish a baseline, here's how much damage the oxygen-loving crew were able to take before an empty room refilled with oxygen at each level of oxygen power:
- level 1 oxygen: 27
- level 2 oxygen: 7
- level 3 oxygen: 4
After a bit more testing, here are my estimates:
- Base oxygen loss is 1% per second
- Level 1 oxygen provides 2% oxygen per second
- Each Lanius in a room drains 10% oxygen per second
- Each Lanius in an adjacent room with an open door drains 7% oxygen per second
- I believe this continues exponentially (the effect reducing by roughly 30% per door). Two Lanius 4 doors apart can drain each other's rooms (and the intervening hallway) at level 3 oxygen, but two Lanius 5 doors apart cannot.
- Oxygen-loving crew begin taking damage at 5% oxygen, at a rate equal to an untrained human's damage output, and to a level 1 Medbay's healing rate (approximately 20 HP every 3 seconds)
In battle, this amounts to:
- 1 Lanius at 0 oxygen power: 9 seconds of 100% damage, then 200% damage thereafter
- 2 Lanius at 0 oxygen power: 5 seconds of 100% damage, then 200% damage thereafter
- 1 Lanius at 1 oxygen power: 11 seconds of 100% damage, then 200% damage thereafter
- 2 Lanius at 1 oxygen power: 5 seconds of 100% damage, then 200% damage thereafter
- 1 Lanius at 2 oxygen power: 19 seconds of 100% damage, then 200% damage thereafter
- 2 Lanius at 2 oxygen power: 6 seconds of 100% damage, then 200% damage thereafter
- 1 Lanius at 3 oxygen power: Oxygen never drains
- 2 Lanius at 3 oxygen power: 11 seconds of 100% damage, then 200% damage thereafter
What this means to beat various races in equal-numbered combat (1 vs 1, 2 vs 2):
- Mantis: The oxygen must drain in under 5 seconds (takes 3 Lanius for a win)
- 2 Lanius get a fair fight at oxygen 1 or less; if the Lanius escape at very low health, the Mantis will likely die of suffocation afterward.
- Rock or Crystal: The oxygen must drain in under 7.5 seconds (takes 2 Lanius, oxygen 2 or less)
- Human, slug: The oxygen must drain in under 15 seconds for an advantage (takes 2 Lanius if oxygen is at 2 or more)
- Engi, single Zoltan: The Lanius will win regardless.
- 2 Zoltan: The oxygen must drain in under 10.5 seconds to ensure survival (takes 2 Lanius if oxygen is powered, takes 3 Lanius if oxygen is at level 3).
- 3 or more Zoltan: Everyone dies.
