I had a similar result this year with180 grain Barnes TTSX from a 300 Weatherby on a cow in brush to mid chest, I put 2 in her at 280 yards, didn't find a blood trail but she climbed up to the ridge after a small circle and 1/2 an hour again behind brush facing the opposite way so the 3rd round through the same area fron 75 yards finally dropped her. The bullet placement was "in between" spine and lungs and the rounds were probably close to 3,000 fps or greater for the last shot.
You could cover all 3 holes with a cigarette pack but they were all too high in the chest to be effective compared to spine or lower lung. My fault for not putting one through the neck instead. The TTSX works best when you catch a rib going in and break the shoulder on exiting. With better placement 2 years ago a larger cow did a back flip and died on the spot with a shot from 550 yards. I prefer the Barnes slip through effect over the NBT blow up on the outside ribs but next time I'll probably take the neck shot rather than high chest, I got lucky retrieving that cow.
