[Even though the fights are being conducted in a shady part of the Nexus, illegal battles tend to attract the rich and powerful citizens of the multiverse. One section of the spectator floor near the cage is almost entirely cut off from the common-folk. Almost being the keyword, as it seems like people are slipping in easily to mingle with the elite and powerful from time to time. It's safe to assume that's what Ice Bear has done as well, given the polar bear (all dressed up), is casually holding conversations with humans and non-humans alike. Looks like someone couldn't resist the chance to make more money as well. If you know him or not, Ice Bear is pretty chill about being approached or helping other gambling-Nexus goers get in on the fun.]
Bears get involved in illegal things too!