What is the meaning of 愣了愣 I have：

格兰仕空调生产车间负责人走过生产线时，看到以为一位工人正在抬起手臂取零件，她愣了愣，想：“这个动作有没有可能改进一下呢？”

她愣了愣， 想  = 'she suddenly thought', 'she, with a start, thought'  Is that the meaning of '愣了愣‘？？ Or is it 'staring at him, she thought, '
愣 is used pretty common in Chinese in a couple of ways. In this situation, the lady 她 could be a little bit shocked, amazed, and surprised. That kind of feeling made her to stare at the scene for a moment.