Jeremy wasn't afraid to take risks as long as there would be a considerable amount of probability of achieving the outcome he wanted. Because of that, he didn't find any reason to not accept Frost Glacier's offer.
And if he didn't accept Frost Glacier's offer, there was a high probability that the three of them would die in Haize's hands. After all, he didn't have any hope of having reinforcements because the strongest among the S-Class students was only Shirley and him while the rest of the students were weaker than them.
If there was one classmate of his that could turn the tide of the battle, then it would be the chuunibyou classmate of his that thought he was a Perfection Realm existence like the Ruler of Reality.
Although that classmate of his had taken the Ruler of Reality's name as well as having the same power as the Ruler of Reality which was reality manipulation, his power was still worthy of being the S-class Classroom Representative.