Even if Plaintiff sues all 3 Defendants, wouldn't D1 and D2's arguments that D3 broke the chain of causation be identical?

Question

I deliberately hedged each defendant's possible negligence.

D₁ (Defendant 1) might've negligently injured P. P falls to the pavement, and bleeds. D₁ panics, and runs away. D₁ is a billionaire.

Next, D₂ might've negligently injured P too. After perhaps negligently injuring P, D₂ drives P to a hospital’s emergency department ("ED"). D2 is bankrupt. D2's net worth is merely $900.

The ED's lone overworked doctor, D₃, might've negligently injured P too. 9 hours after being admitted to the ED, P dies.

Discuss merely all parties’ tortious liability. Ignore — do NOT discuss — damages.

D₁ shall try to argue that D₂ and D₃ broke the chain of causation.

D₂ shall try to argue that D₃ broke the chain of causation. Obviously D₁'s argument differs from D₂'s — because D₁ antedated 2 potential intervening acts, but D₂ antedated merely 1 potential intervening act.

1. But wouldn't D₁'s argument that D₃ broke the chain of causation, be the exact same as D₂'s argument that D₃ broke the chain of causation? If not, why not?

2. In other words, imagine that D₁ wrote his Statement of Defence before D₂. After deleting all of D₁'s paragraphs on D₃ and changing D₁ to D₂, can't D₂ just copy and paste D₁'s Statement of Defence?

Answer 1

Causation flows forwards in time

Therefore, D1 can argue it was broken by D2 or D3 and D2 can argue it was broken by D3; all other combinations can’t break causation.

What constitutes breaking causation or novus actus interveniens?

Australian Courts have consistently held that to establish a novus actus interveniens capable of severing the chain of causation, the original tortfeasor must establish, on the balance of probabilities, that the subsequent treatment was “grossly negligent”, and therefore not a reasonably foreseeable consequence of the original injury. A mere error or lapse of judgment will not possess enough “causal potency” to amount to an intervening act capable of breaking the chain of causation.

Australian authorities suggest that medical treatment which is unforeseeable is treatment that is “inexcusably bad”, “completely outside the bounds of what any other reputable medical practitioner might prescribe”, or “so obviously unnecessary or improper that it is in the nature of a gratuitous aggravation of the injury” or “extravagant from the point of view of medical practice or routine.” For your example, D2 did not break causation - further injury during transport is not unforeseeable. D3 did break causation - forgetting a patient for 9 hours is “inexcusably bad”.

In terms of liability:

D1 might be liable. However, the “accident” must amount to negligence. If D1 did not owe a duty of care or complied with that duty and the injury was due to pure accident, then they are not liable. The breaking of the chain by D3 means they are only liable for the injuries sustained before then. However, many jurisdictions impose a duty to render aid on a person that caused an accident even if they were not negligent in doing so. Whether D1 leaving the scene creates liability or is merely criminal depends on the specifics of such a law.

D2 probably isn’t liable. In the circumstances, dropping P is likely to be considered a pure accident. In any event, D2 is probably protected by Good Samaritan laws.

D3 is liable, unless P’s injuries were already fatal. That is, there was no possible medical intervention that could be done that would change the fatal outcome.