Yes, I do think significant damage was done--in a brief time. My biggest problem with the breaching tool/hammer being the murder weapon is that her body was said to have been found in the SW quadrant of the building. The FOIA snippet upthread further appeared to indicate a reporting officer saw her body lying face up in the hallway somewhere between the SW entrance entrance and the kitchen on the N end of the building. SW quadrant would seem to indicate she got no further walking northward than the main W foyer. Waaay back in earlier threads, while I still leaned towards a firearm being the actual thing that delivered the lethal puncture, I'd been considering that she was attacked in the SW entryway vestibule (due to no camera record of the attack).
But with the snippet, I'm now theorizing she was brought down in the hallway. Seems the snippet indicates she was found in the N/S hallway on the west side of the building, in the SW quadrant of the building. Because of the hallway I'm leaning further away from even a two-minute attack with a breaching tool/hammer, since it seems that action should have been caught by the N/S hallway motion detectors (considering where her body was found).
Considerable damage was done to her body, the force seemingly indicating close range, yet no video of even a 2-minute confrontation in that hall, and no video of her attacker's escape. So the only way I can figure it in light of all the other facts we know about the case is that SP hid himself in the main W entrance foyer (no cameras in evidence there in the pre-attack photos), possibly hiding behind the column there right near the N/S hall, and then fired on her with particularly damaging ammo as she walked from the SW entrance in a northerly (toward the kitchen) direction. He did not approach her there in the hall, nor continue to attack with breaching tool--as that would've been caught on camera. (No motion cameras were compromised according to LE.) Nor would he have had to, as the damage he'd done was likely obvious at that close range. He then exited straightway out the front W entrance doors. Wearing all black at that hour, with no indoor or outdoor cameras to capture his escape, his exit was not witnessed or filmed (as it would by any other exit requiring hallway passage).
Using Jethro's detailed map, here, the red circled area is the column area where I theorize SP lay in wait; the red "X" is roughly where I imagine she was felled by bullets to head and chest. The snippet described her as being on her back, which may be because CPR was attempted. But if her position hadn't been changed, it also fits with being felled by a firearm blast from the front.
JMO and all theory at this point.
ETA: good photo of that column in arkansasmimi's post above (#402).