Tyson is digging his own grave.
He has been doing that for years. He doesn’t exactly want to die, but equally, Tyson is not particularly attached to living either. He won’t throw away his life pointlessly and Tyson isn’t actively looking for ways to die, but the value he places on his own life is impossibility low.
Tyson puts the fact that there are people that still depend on him, that there is still work to be done, far higher than the simple need to continue living into his motivations for continuing to live. It’s a motivation that has kept him going for years, but it’s a dangerous one that will eventually end him if the benefits to others by his death outweigh those by his continued existence in Tyson’s mind.
The former Lieutenant is in a curious position, especially from a medical intervention stance. His disinterest in his own life is not an active danger to himself or others, and yet he’s clearly courting death and will continue to do so until it eventually kills him. He could live for years, or days, on the flip of a coin.