Citi Technical Leadership Program Intern interview questions

I submitted my resume through Purdue's career fair. After around 2 weeks, I received an e-mail telling me that I was selected to have a first round interview. It was a skype interview, you have to make sure that they were on your contact list before the interview starts. The first round was pretty easy, most likely behavior questions and some details about my resume. After 2 hours, I received a call that they told me they would like to do a second round which is the last round interview right away. It was still a skype interview, they won't look at your resume this time. A senior manager and another TLP intern recruited me. Questions were very difficult to answer.