star trek - Why didn't Seven of Nine assimilate the Voyager crew when she was separated from the collective?

In the episode Scorpion: Part II Seven of Nine is separated from the collective when Chakotay uses a temporary neural link to sabotage the console she is using, permanently destroying her neural link.

Later, in The Gift

[Seven] is not used to being an individual and she repeatedly demands that she be returned to the Collective. Janeway refuses, and asks her to help with removing the Borg technology in Voyager's systems.

Seven threatens to kill Janeway when the Captain enters her cell in the brig intentionally unarmed. Seven even physically strikes her out of anger.

Why didn't Seven assimilate Janeway using nanoprobes when she was within striking distance? She had her tubules and her nanoprobes at that point and is shown using them for the rest of the series.

For example:

A couple of years after the above in the episode Inside Man; Ferangi hijack a hologram of Reginald Barclay in an attempt to send Seven's dead body through a geodesic fold so that they could harvest and sell her borg nanoprobes.

Also, in Body and Soul the Doctor is forced to upload his program to Seven's borg implants to hide from photonic (hologram) hunters. She uses her borg tubules to interface with his mobile emitter.

Further, the Memory Alpha entry on the Borg states:

Cybernetic implants were either surgically attached to the body or grown internally by nanoprobes injected into the bloodstream.

As she had these nanoprobes, what is the in universe reason that she gave up so easily and why didn't she attempt to assimilate the captain when she had the chance? She was enraged at the thought of not returning to the collective and reacted violently, why only that?

Answer

Two reasons.

First, in Dark Frontier the Borg Queen says she allowed Seven to be "liberated" and the long range intent was to recapture her later and use her and what she had learned. With such a plan, the Queen would have made subtle programming changes to keep Seven from assimilating the Voyager crew and to, instead, observe them. I think this is the strongest argument against her assimilating humans as fast as she can.

Second, it wouldn't gain her any tactical advantage. Two Borg in the brig would not gain much over one Borg in the brig. Whether Seven intended to work with the Voyager crew or not, if she assimilated Janeway at that point, she'd lose any possibility of being left unguarded or let out of the brig. It would be a bigger tactical advantage to gain trust (which would be part of the Borg Queen's programming with the first point), then to try to fight from a trapped position with no likely way out. She'd be much better off assimilating someone after she's released from the brig than while she (and her target) are inside the brig and under complete control of the Voyager crew.

@Plutor also has a good point, too.