Actually, in my experience, it's MUCH EASIER to skate right after someone has killed it and the roof has been blown off the building. You can absorb ALL of that energy and use it for yourself -- there is a TON of energy in the building right after someone has killed it. Yes, you have to block out that score and placement (if they are being announced) but there's just something about the response for that previous skater as you take the ice that carries you. Personally, my best performances are typically right after someone else has totally killed it. The great thing about having the person before you kill it is the crowd is already "warmed up" for you and the energy level is SUPER high.
I saw the look on Nagasu's face when the place erupted after Alissa skated in 2011 and she looked defeated - even before she had been announced to take the ice and it wasn't like only one American lady was going to Worlds...
Nagasu has not been a good "placement pressure" skater. The expectations were low when she made the Olympic team (everyone expected it to be Cohen and...). The expectations for placement at the Olympics was not really there - if anyone was going to be top 5, it was more expected to be Flatt since she was the US champion (that could be debated, but still...) and no one expected either American to challenge for a medal. When she won her National title in 2008, no one expected HER to win (Flatt, Zhang, Meissner...). When she won the SP at Worlds in 2010 and the expectations to "finish" were on her, she blew the opportunity. She had been injured throughout the summer after and her GP season was a little down after that, but she won the SP at Nationals after Czsiny had won the GP final and then she blew that opportunity and finished 3rd. In 2009, she came in as defending National Champion and had issues and ended up 5th. Last year, she was in the final group after the SP within striking distance of the World team and knew Zawadski had a propensity for poor LP, Zhang was still coming back, Czsiny had been skating inconsistently in general, Wagner was someone she had beaten repeatedly over time, and Gao is perpetually 5th, but blew her opportunity BIG TIME to finish 7th behind a Rachel Flatt who skated her LP in the penultimate group. Maybe she will skate well at Nationals this year because the expectations are back to low? Who knows...I know that she seems to be psychologically fragile when there is pressure for placement.