So, I see you want to know all about my character's connections to death? Alright, here's a rough tally, in chronological order for you. I don't know if the amount of deaths factors in at all, or the nature of the death, but let's do this! Some of this is my headcanon, but since I'm writing her, it's pertinent information, I think.

As Caroline (I don't know if he can sense her or not?)
Countless testing casualties, she would heave had to do the tallies on this, if nothing else. She very likely witnessed at least some directly, and there was a wide array of exciting ways to eat dirt in Aperture, so.
Cave Johnson's slow death. She watched the man wither away for years, and tried her best to keep him alive.
Being uploaded, her body definitely died that day. Arguably, a large part of her as a person died, too.

As GLaDOS
Incalculable casualties as a direct result of her fumigating the facility.
The survivors were run through testing until they died of exhaustion.
Deliberately corrupting and destroying personality constructs, some remained active and were rendered useless, some ceased to function entirely. Dealer's choice.
Multiple counts of attempted murder against on Doug Rattmann, and one Chell [REDACTED].
She died, and was forced to relive her death on repeat for an unspecified length of time.

Am I missing anybody? I don't think I forgot anyone I've killed. I mean, I never did write down their names, but I remember every moment of it.