Frankly, if you're applying to a comepetitive resdiency, then reasearch DOES matter - but not the crappy two months you're going to do over the summer. True, you MIGHT get something good out of it, but if you're really set on a super-competitive specialty, then you'll probably end up having to take a year off to do meaningful research anyway. So, enjoy the summer and do something cool with it.
If, on the other hand, you're NOT planning on going into a competitive specialty, then research really DOESN'T matter, in which case you would again be better off taking the summer to travel or do medical work abroad.
Oh, and don't forget to consider the fact that MS2 is very long, very hard, and can be demoralizing at times. If you didn't go away and travel over the summer like you wanted, you might regret it... which *could* make you a bitter 2nd year...
So... you know my opinion 😀.