When a British Agent is accused of aiding the terrorist attack she failed to foil, she is forced to go on the run from, and on the hunt for, both friends and foes.

My tweak:
When a British agent is accused of aiding a terrorist attack she failed to foil, she must prove her innocence while on the run from coworkers and conspirators.
(28 words)

Notes:
My tweak explicitly includes her objective goal, what she must do while on the lam.
I have no problem with the inciting incident being the accusation.? That's when the action of the plot proper begins? Until she's accused she has no need to run, no need to prove her innocence.? Everything else before that event is setup.
I? used "coworkers" instead of friends because aren't her erstwhile friends now her foes?? But that's picky, optional.
And "conspirators" to preserve the alliteration.? But again, that's picky, optional.

fwiw

My tweak:
When a British agent is accused of aiding a terrorist attack she failed to foil, she must prove her innocence while on the run from coworkers and conspirators.
(28 words)

Notes:
My tweak explicitly includes her objective goal, what she must do while on the lam.
I have no problem with the inciting incident being the accusation.? That's when the action of the plot proper begins? Until she's accused she has no need to run, no need to prove her innocence.? Everything else before that event is setup.
I? used "coworkers" instead of friends because aren't her erstwhile friends now her foes?? But that's picky, optional.
And "conspirators" to preserve the alliteration.? But again, that's picky, optional.

fwiw

"being accused" should take place later (around the midpoint) to raise stakes. Instead your logline would benefit from "failing to prevent detonation" as an inciting incident

Also, "to run away from friends and foes" is an action for the Goal "to prove his innocence"

Another version could be --
??? When a counterterrorist fails to prevent a detonation, he must prove his innocence while evading both his friends and foes ???

The premise is interesting and would benefit from a peculiar detail, which would seperate it from similar films....like "the fugitive" (1993) which has the same gameplay verb for protagonist

Good Luck Daryl Rogerson