According to a case report about a 24-year old woman (PubMed Central), in agoraphobia, during a panic attack, the sympathetic nervous system is activated, which results in adrenaline release, which causes symptoms, such as:
...pounding heart, shortness of breath nervousness, dizziness, losing control on himself for few minutes.
So, from symptoms lasting few minutes, you can conclude that adrenaline is acting for few minutes and not all the time.
According to one 2005 study, caffeine stimulates adrenaline release, but
adrenaline alone does not account for the effects of caffeine and additional mechanisms must be involved.
So, from the above, one could think that caffeine could help you stay alert, despite already being stimulated by adrenaline from anxiety.
But, according to one 2015 review article:
moderate-to-high consumers develop tolerance to caffeine and only low or nonconsumers can eventually benefit from an acute administration.
In conclusion, if your buddy drinks a lot of coffee on a daily basis, she has probably developed tolerance to caffeine, in which case the wakening effect would be probably a placebo effect.