That silence is the whole problem right there. It puts you on the spot in a really bad way. Maybe it's just me but asking for that much money in a social setting feels like a trap. A real friend would ask privately so you can say no without an audience. The way they asked seems more about pressure than need.
Yeah totally agree @the_holly. I had a buddy ask me for a loan like that once in front of a group. I just said "hey man text me later" and changed the subject. Let him know he could hit me up private but I wasn't gonna be the bad guy in front of everyone.