So I actually like this game more than REmake 2, which is surprising to me because I liked the original RE2 a lot more than the original RE3. And because Claire and Leon were my two favorite main characters (along with Ada if she counts), while Jill was whatever to me.
This game however made Jill my favorite main character now, while Claire is someone I now dislike.
When Claire said "I got this" in REmake 2, I thought to myself "No you don't."
She had no business feeling so confident against the final boss having no special weapons or training for that matter, when the person she interrupted did have a special weapon.
This doesn't make much sense to me. For reference, I'm only playing the RE2 Remake now, and it's my first RE game period (outside of playing brief sections of RE4 at a friend's place back in the day), so I have no idea what Claire was like before as a character.
With that out of the way, let's get to what you just described. At this point in the game (pretty much the end), Claire has already fought off the G-Virus monster twice before, to go along with all the other shit she's survived on her journey through the game, so she does have some reason to be confident that she can, at the very least, disable this monster yet again.
As for special weapons....she's got a damn grenade launcher. The "special weapon" the doctor lady had pretty much did fuck all after the first shot, and Claire didn't so much "interrupt" her, as stop someone that could barely stand from getting torn to shreds in the next few seconds. I suppose she could have taken the little cryo-gun off her, but again, it didn't seem to be particularly effective, beyond setting up the gotcha moment the story really wanted.